CVE-2026-53266VulnerabilityPublished 28 Oct 2026

Red Hat Security Advisory: kpatch-patch-5_14_0-427_100_1, kpatch-patch-5_14_0-427_113_1

Affects Red HatSource GCVE Database

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Mentioned vulnerabilities

Exploited in the wild · KEV due 21 Sep 2026 : apply the vendor's fix or mitigations to Red Hat now.

Data as of 29 Oct 2026, 08:27 UTC

Exploitation

Actively exploited

High severity · CVSS not yet scored by NVD

KEV deadline: 21 Sep 2026 US federal agencies must patch by this date; a sensible deadline for everyone else. Other KEV due dates
EPSS: 0.9% chance of exploitation in 30 days – higher than 60% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
Public exploit code: GitHub proofs of concept
Exploited in the wildExploited: evidence found.
Listed in CISA KEV 40 days before disclosure
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

Added to CISA KEV (opens in a new tab)
exploitation confirmed
18 Sep 2026, 40 days before disclosure
KEV remediation due
US federal deadline
21 Sep 2026, 37 days before disclosure
CVE published
on cve.org
28 Oct 202610:43 UTC, t = 0
In Threat Radar
record ingested
29 Oct 202607:07 UTC, 20 hours after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), GitHub proofs of concept, CISA KEV (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

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Affected software

Product	Affected	Fixed in
Red Hat Product Security Red Hat	Affected Red Hat Red Hat Enterprise Linux Red Hat Enterprise Linux BaseOS E4S (v.9.4) src kpatch-patch-5_14_0-427_100_1-0:1-17.el9_4.src	Fixed in–

Description

Red Hat has issued a security advisory for a kernel live patch module targeting kernel-5.14.0-427.100.1.el9_4. The update addresses multiple vulnerabilities in the Linux kernel, including issues in netfilter, pppoe, bridge, packet, and xfrm subsystems. These vulnerabilities involve improper memory handling and validation errors that could potentially be exploited. The advisory rates the security impact as Important and notes known exploitation in the wild. The update is available as kpatch patches for Red Hat Enterprise Linux 9.4 variants.

Impact

The vulnerabilities fixed by this advisory affect kernel networking components and involve improper memory writes, pointer handling, and validation errors. These issues could allow attackers to cause system instability, crashes, or potentially execute arbitrary code or escalate privileges via crafted network packets. The advisory rates the impact as Important and confirms known exploitation in the wild, indicating active threats leveraging these flaws.

Mitigation

Red Hat has released updated kpatch live patch modules for kernel-5.14.0-427.100.1.el9_4 and related variants that address these vulnerabilities. Users should apply these official patches promptly to remediate the issues. Detailed instructions for applying the updates are available in the Red Hat advisory article at https://access.redhat.com/articles/11258. No additional mitigation steps are indicated beyond applying the provided patches.

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-805Buffer Access with Incorrect Length Value (opens in a new tab)
Base weaknessLikelihood of exploit: High
The product uses a sequential operation to read or write a buffer, but it uses an incorrect length value that causes it to access memory that is outside of the bounds of the buffer.
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 · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
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)
Attack patterns
Overflow Buffers (opens in a new tab)
SOAP Array Overflow (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-787Out-of-bounds Write (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #5
The product writes data past the end, or before the beginning, of the intended buffer.
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 · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
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

Timeline

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Oct 2026, 07:26 UTC

Public exploits and detectionGitHub proofs of concept

WeaknessesCWE-825, CWE-805, CWE-787

Technical details

References

Community reviews

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