CVE-2024-56633VulnerabilityPublished 19 May 2026Updated 30 Oct 2026

Red Hat Security Advisory: kernel security update

Affects Linux kernelSource GCVE Database

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Mentioned vulnerabilities

Not known to be exploited.

Data as of 30 Oct 2026, 06:59 UTC

Severity

Medium

Rated by Threat Radar · No CVSS score from NVD or the CNA

EPSS: 0.2% chance of exploitation in 30 days – higher than 20% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation evidence

Disclosed: evidence found.
CVE published 19 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Red Hat Product Security Red Hat	Affected Red Hat Red Hat Enterprise Linux Red Hat Enterprise Linux AppStream (v. 10) Red Hat Enterprise Linux BaseOS (v. 10) Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)	Fixed in–

AI-suggested

An official security update is available from Red Hat for Red Hat Enterprise Linux 10 and related products. Users should apply the kernel update provided in advisory RHSA-2026:18134 and reboot affected systems to ensure the fixes take effect. Detailed update instructions are available at https://access.redhat.com/articles/11258. No additional mitigations are specified beyond applying the official patch and rebooting.

Description

The kernel packages contain the Linux kernel, the core of any Linux operating system. Security Fix(es): * kernel: tcp_bpf: Fix the sk_mem_uncharge logic in tcp_bpf_sendmsg (CVE-2024-56633) * kernel: KVM: x86: Load DR6 with guest value only before entering .vcpu_run() loop (CVE-2025-21839) * kernel: block: fix resource leak in blk_register_queue() error path (CVE-2025-37980) * kernel: dmaengine: idxd: fix memory leak in error handling path of idxd_alloc (CVE-2025-38015) * kernel: espintcp: remove encap socket caching to avoid reference leak (CVE-2025-38097) * kernel: bpf: fix ktls panic with sockmap (CVE-2025-38166) * kernel: bpf: Check rcu_read_lock_trace_held() in bpf_map_lookup_percpu_elem() (CVE-2025-38202) * kernel: bpf: Do not include stack ptr register in precision backtracking bookkeeping (CVE-2025-38279) * kernel: ring-buffer: Do not trigger WARN_ON() due to a commit_overrun (CVE-2025-38267) * kernel: phy: qcom-qmp-usb: Fix an NULL vs IS_ERR() bug (CVE-2025-38275) * kernel: ftrace: Fix UAF when lookup kallsym after ftrace disabled (CVE-2025-38346) * kernel: ACPICA: fix acpi operand cache leak in dswstate.c (CVE-2025-38345) * kernel: nvmet: fix memory leak of bio integrity (CVE-2025-38405) * kernel: netfilter: flowtable: account for Ethernet header in nf_flow_pppoe_proto() (CVE-2025-38441) * kernel: net: vlan: fix VLAN 0 refcount imbalance of toggling filtering during runtime (CVE-2025-38470) * kernel: fs: writeback: fix use-after-free in __mark_inode_dirty() (CVE-2025-39866) * kernel: PCI/AER: Avoid NULL pointer dereference in aer_ratelimit() (CVE-2025-40034) * kernel: dm: fix NULL pointer dereference in __dm_suspend() (CVE-2025-40134) * kernel: Revert "NFSD: Remove the cap on number of operations per NFSv4 COMPOUND" (CVE-2025-40210) * kernel: Linux kernel MPTCP: Privilege escalation or denial of service via use-after-free in timer handling (CVE-2025-40257) * kernel: smb: client: fix potential cfid UAF in smb2_query_info_compound (CVE-2025-40320) * kernel: wifi: mac80211_hwsim: fix typo in frequency notification (CVE-2026-23040) * kernel: Kernel: Privilege escalation or denial of service in nf_tables via inverted element activity check (CVE-2026-23111) * kernel: Linux kernel: Denial of Service in ice driver due to race condition during VSI rebuild (CVE-2026-23210) * kernel: Linux kernel: Denial of service and memory corruption in RDMA umad (CVE-2026-23243) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section. Additional Changes: For detailed information on changes in this release, see the Red Hat Enterprise Linux 10 Release Notes linked from the References section.

Impact

The vulnerabilities fixed by this update could lead to privilege escalation, denial of service, memory corruption, resource leaks, and kernel panics in affected Red Hat Enterprise Linux 10 systems. Exploitation could allow attackers to disrupt system stability or escalate privileges, impacting system security and availability. However, no known exploits in the wild have been reported at the time of this advisory. The overall security impact is rated moderate by Red Hat.

Summary

The advisory covers a comprehensive kernel security update for Red Hat Enterprise Linux 10, fixing 25 distinct CVEs affecting multiple kernel components. Key fixes include correcting sk_mem_uncharge logic in tcp_bpf_sendmsg (CVE-2024-56633), preventing privilege escalation and denial of service via use-after-free in MPTCP timer handling (CVE-2025-40257), fixing memory leaks in DMA engine and block device subsystems, addressing null pointer dereferences in PCI/AER and device mapper suspend paths, and resolving various BPF and netfilter issues. The update mitigates risks of resource leaks, kernel panics, race conditions, and potential privilege escalations. The advisory references detailed CVE pages for individual vulnerabilities and requires rebooting systems to apply the fixes.

CWE-99Improper Control of Resource Identifiers (Resource Injection) (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A05:2025: Injection (opens in a new tab)
The product receives input from an upstream component, but it does not restrict or incorrectly restricts the input before it is used as an identifier for a resource that may be outside the intended control sphere.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
Injection Prevention (opens in a new tab)
SQL Injection Prevention (opens in a new tab)
Injection Prevention in Java (opens in a new tab)
OWASP ASVS 4.0.3
V1.5.1 (opens in a new tab)
Attack patterns
Buffer Overflow via Environment Variables (opens in a new tab)
Manipulating Writeable Configuration Files (opens in a new tab)
Resource Injection (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-665Improper Initialization (opens in a new tab)
Class weaknessLikelihood of exploit: Medium
The product does not initialize or incorrectly initializes a resource.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Architecture and Design
Identify all variables and data stores that receive information from external sources, and apply input validation to make sure that they are only initialized to expected values.
Implementation
Explicitly initialize all your variables and other data stores, either during declaration or just before the first usage.
Attack patterns
Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions (opens in a new tab)
Leveraging Race Conditions (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-459Incomplete Cleanup (opens in a new tab)
Base weakness
The product does not properly "clean up" and remove temporary or supporting resources after they have been used.
Architecture and Design · Implementation
Temporary files and other supporting resources should be deleted/released immediately after they are no longer needed.
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-772Missing Release of Resource after Effective Lifetime (opens in a new tab)
Base weaknessLikelihood of exploit: High
The product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation
It is good practice to be responsible for freeing all resources you allocate and to be consistent with how and where you free resources in a function. If you allocate resources that you intend to free upon completion of the function, you must be sure to free the resources at all exit points for that function including…
Operation · Architecture and Design · Resource Limitation
Use resource-limiting settings provided by the operating system or environment. For example, when managing system resources in POSIX, setrlimit() can be used to set limits for certain types of resources, and getrlimit() can determine how many resources are available.
Attack patterns
HTTP DoS (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-131Incorrect Calculation of Buffer Size (opens in a new tab)
Base weaknessLikelihood of exploit: High
The product does not correctly calculate the size to be used when allocating a buffer.
Implementation
When allocating a buffer for the purpose of transforming, converting, or encoding an input, allocate enough memory to handle the largest possible encoding. For example, in a routine that converts "&" characters to "&" for HTML entity encoding, the output buffer needs to be at least 5 times as large as the input…
Implementation
Understand the programming language's underlying representation and how it interacts with numeric calculation (CWE-681). Pay close attention to byte size discrepancies, precision, signed/unsigned distinctions, truncation, conversion and casting between types, "not-a-number" calculations, and how the language handles…
Implementation · Input Validation
Perform input validation on any numeric input by ensuring that it is within the expected range. Enforce that the input meets both the minimum and maximum requirements for the expected range.
Attack patterns
Overflow Buffers (opens in a new tab)
Buffer Overflow via Parameter Expansion (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-414Missing Lock Check (opens in a new tab)
Base weakness
A product does not check to see if a lock is present before performing sensitive operations on a resource.
Architecture and Design · Implementation
Implement a reliable lock mechanism.
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-821Incorrect Synchronization (opens in a new tab)
Base weakness
The product utilizes a shared resource in a concurrent manner, but it does not correctly synchronize access to the resource.
CWE-476NULL Pointer Dereference (opens in a new tab)
Base weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #13OWASP Top 10 A10:2025: Mishandling of Exceptional Conditions (opens in a new tab)
The product dereferences a pointer that it expects to be valid but is NULL.
Implementation
For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
Requirements
Select a programming language that is not susceptible to these issues.
Implementation
Check the results of all functions that return a value and verify that the value is non-null before acting upon it.
OWASP Cheat Sheets
Logging (opens in a new tab)
Error Handling (opens in a new tab)
OWASP ASVS 4.0.3
V11.1.7 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-824Access of Uninitialized Pointer (opens in a new tab)
Base weakness
The product accesses or uses a pointer that has not been initialized.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-416Use After Free (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #7
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Architecture and Design · Language Selection
Choose a language that provides automatic memory management.
Implementation · Attack Surface Reduction
When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-908Use of Uninitialized Resource (opens in a new tab)
Base weaknessLikelihood of exploit: Medium
The product uses or accesses a resource that has not been initialized.
Implementation
Explicitly initialize the resource before use. If this is performed through an API function or standard procedure, follow all required steps.
Implementation
Pay close attention to complex conditionals that affect initialization, since some branches might not perform the initialization.
Implementation
Avoid race conditions (CWE-362) during initialization routines.
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-911Improper Update of Reference Count (opens in a new tab)
Base weaknessLikelihood of exploit: Medium
The product uses a reference count to manage a resource, but it does not update or incorrectly updates the reference count.
CWE-703Improper Check or Handling of Exceptional Conditions (opens in a new tab)
Pillar weaknessOWASP Top 10 A10:2025: Mishandling of Exceptional Conditions (opens in a new tab)
The product does not properly anticipate or handle exceptional conditions that rarely occur during normal operation of the product.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
OWASP Cheat Sheets
Logging (opens in a new tab)
Error Handling (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-770Allocation of Resources Without Limits or Throttling (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #25
The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
Requirements
Clearly specify the minimum and maximum expectations for capabilities, and dictate which behaviors are acceptable when resource allocation reaches limits.
Architecture and Design
Limit the amount of resources that are accessible to unprivileged users. Set per-user limits for resources. Allow the system administrator to define these limits. Be careful to avoid CWE-410.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V8.1.4 (opens in a new tab)
V13.4.1 (opens in a new tab)
V11.1.4 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Exponential Data Expansion (opens in a new tab)
Serialized Data Parameter Blowup (opens in a new tab)
Serialized Data with Nested Payloads (opens in a new tab)
Oversized Serialized Data Payloads (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-366Race Condition within a Thread (opens in a new tab)
Base weaknessLikelihood of exploit: Medium
If two threads of execution use a resource simultaneously, there exists the possibility that resources may be used while invalid, in turn making the state of execution undefined.
Architecture and Design
Use locking functionality. This is the recommended solution. Implement some form of locking mechanism around code which alters or reads persistent data in a multithreaded environment.
Architecture and Design
Create resource-locking validation checks. If no inherent locking mechanisms exist, use flags and signals to enforce your own blocking scheme when resources are being used by other threads of execution.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V1.11.2 (opens in a new tab)
Attack patterns
Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions (opens in a new tab)
Leveraging Race Conditions (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-825Expired Pointer Dereference (opens in a new tab)
Base weakness
The product dereferences a pointer that contains a location for memory that was previously valid, but is no longer valid.
Architecture and Design
Choose a language that provides automatic memory management.
Implementation
When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-833Deadlock (opens in a new tab)
Base weakness
The product contains multiple threads or executable segments that are waiting for each other to release a necessary lock, resulting in deadlock.
Attack patterns
Forced Deadlock (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-672Operation on a Resource after Expiration or Release (opens in a new tab)
Class weakness
The product uses, accesses, or otherwise operates on a resource after that resource has been expired, released, or revoked.
CWE-1204Generation of Weak Initialization Vector (IV) (opens in a new tab)
Base weakness
The product uses a cryptographic primitive that uses an Initialization Vector (IV), but the product does not generate IVs that are sufficiently unpredictable or unique according to the expected cryptographic requirements for that primitive.
Implementation
Different cipher modes have different requirements for their IVs. When choosing and implementing a mode, it is important to understand those requirements in order to keep security guarantees intact.
OWASP Cheat Sheets
Forgot Password (opens in a new tab)
OWASP ASVS 4.0.3
V2.3.1 (opens in a new tab)
V2.6.2 (opens in a new tab)
V2.7.6 (opens in a new tab)
Attack patterns
Encryption Brute Forcing (opens in a new tab)
Cryptanalysis (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

GCVE source: db.gcve.eu
Csaf Category: csaf_security_advisory
Csaf Version: 2.0
Publisher: Red Hat Product Security
Advisory ID: RHSA-2026:18134
CVE Count: 25
Additional Cves: CVE-2025-21839, CVE-2025-37980, CVE-2025-38015, CVE-2025-38097, CVE-2025-38166, CVE-2025-38202, CVE-2025-38267, CVE-2025-38275, CVE-2025-38279, CVE-2025-38345, CVE-2025-38346, CVE-2025-38405, CVE-2025-38441, CVE-2025-38470, CVE-2025-39866, CVE-2025-40034, CVE-2025-40134, CVE-2025-40210, CVE-2025-40257, CVE-2025-40320, CVE-2026-23040, CVE-2026-23111, CVE-2026-23210, CVE-2026-23243

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 12 Jul 2026, 10:05 UTC

WeaknessesCWE-99, CWE-665, CWE-459 +16

Technical details

References

Community reviews

Related threats