CVE-2025-38248VulnerabilityPublished 22 Apr 2026Updated 21 Aug 2026

Red Hat Security Advisory: kernel-rt security update

Affects Red HatSource GCVE Database

Mentioned vulnerabilities

Not known to be exploited · fixed in 5.15.0-1110.119~20.04.1 : update Red Hat when convenient.

Data as of 25 Oct 2026, 19:02 UTC

Severity

Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 22% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 5.15.0-1110.119~20.04.1, 5.15.0-1100.109~20.04.1, 5.15.0-1100.107~20.04.2 +2

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 2026-10-25.

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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC 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

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
Red Hat Product Security Red Hat	Affected Red Hat Red Hat Enterprise Linux Red Hat Enterprise Linux Real Time E4S (v.9.2) Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) src <5.15.0-1100.107~20.04.2 <5.15.0-1110.119~20.04.1 <5.15.0-1100.109~20.04.1 <5.15.0-170.180~20.04.3 <5.15.0-1094.97~20.04.1	Fixed in 5.15.0-1100.107~20.04.2 5.15.0-1110.119~20.04.1 5.15.0-1100.109~20.04.1 5.15.0-170.180~20.04.3 5.15.0-1094.97~20.04.1

AI-suggested

Red Hat has released an official security update (RHSA-2026:9512) that addresses these vulnerabilities in the kernel-rt packages for Red Hat Enterprise Linux 9.2 Real Time variants. Users should apply the update as described in the Red Hat advisory (https://access.redhat.com/articles/11258) and reboot the system to ensure the fixes take effect. No alternative mitigations are indicated by the vendor advisory.

Description

The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements. Security Fix(es): * kernel: Linux kernel:A use-after-free in bridge multicast in br_multicast_port_ctx_init (CVE-2025-38248) * kernel: Bluetooth: MGMT: Fix possible UAFs (CVE-2025-39981) * kernel: mlxsw: spectrum_mr: Fix use-after-free when updating multicast route stats (CVE-2025-68800) * kernel: Linux kernel: Denial of Service via unsafe requeue in rxrpc_recvmsg (CVE-2026-23066) * kernel: Linux kernel: Local denial of service and memory leak in DAMON sysfs via setup failure (CVE-2026-23144) * kernel: Linux kernel: Use-after-free in bonding module can cause system crash or arbitrary code execution (CVE-2026-23171) * kernel: macvlan: fix error recovery in macvlan_common_newlink() (CVE-2026-23209) * kernel: net/sched: cls_u32: use skb_header_pointer_careful() (CVE-2026-23204) * kernel: kernel: Privilege escalation or denial of service via use-after-free in nf_tables_addchain() (CVE-2026-23231) 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.

Impact

Successful exploitation of these vulnerabilities could lead to system crashes, denial of service, privilege escalation, memory leaks, or arbitrary code execution on affected Red Hat Enterprise Linux Real Time systems. The vulnerabilities affect critical kernel components responsible for networking, Bluetooth management, and system resource monitoring, potentially impacting system stability and security.

Summary

The Red Hat kernel-rt packages for Real Time Linux kernels contain multiple security vulnerabilities including use-after-free bugs (CVE-2025-38248, CVE-2025-39981, CVE-2025-68800, CVE-2026-23171, CVE-2026-23231), denial of service conditions (CVE-2026-23066, CVE-2026-23144, CVE-2026-23231), and memory leaks (CVE-2026-23144). These vulnerabilities affect various kernel subsystems such as bridge multicast, Bluetooth MGMT, mlxsw spectrum multicast routing, rxrpc, DAMON sysfs, bonding, macvlan, net scheduler cls_u32, and nf_tables. Exploitation could result in system crashes, privilege escalation, or arbitrary code execution. Red Hat Product Security issued advisory RHSA-2026:9512 providing updated kernel-rt packages for Red Hat Enterprise Linux 9.2 Real Time variants to remediate these issues. The update must be applied and the system rebooted for the fixes to take effect.

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-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-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-1285Improper Validation of Specified Index, Position, or Offset in Input (opens in a new tab)
Base weakness
The product receives input that is expected to specify an index, position, or offset into an indexable resource such as a buffer or file, but it does not validate or incorrectly validates that the specified index/position/offset has the required properties.
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
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).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 12 Jul 2026, 09:33 UTC

WeaknessesCWE-825, CWE-416, CWE-772 +1

Technical details

References

Community reviews

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