CVE-2026-98442
Description
A flaw was found in the Linux kernel's traffic control connection tracking action (act_ct). An attacker capable of sending network traffic handled by the affected system can cause a Denial of Service (DoS) or kernel memory corruption through a use-after-free vulnerability. This issue occurs because connection tracking helpers record pointers to extension memory before all extensions are added, leaving invalid references when memory is subsequently reallocated.
Mitigation
--- CME Mitigation Guidance (2026-10-20) ---
Disclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure.
The highest-value action is to ensure conntrack helper functions run only after all connection tracking extensions have been finalized in traffic control act_ct processing: upgrade to the fixed Kernel/Kernel Ivos Qualcomm/Kernel Rt/Openshift/Ose Rhel Coreos/Kpatch builds, which reorder act_ct operations to invoke conntrack helpers after all connection extensions are allocated and added, closing all 2 injection vectors (crafted network packets processed by act_ct, unconfirmed connection tracking extension reallocation). Until patched, this is a concern on Linux systems running traffic control with connection tracking action act_ct and conntrack helpers enabled, so audit and restrict traffic control act_ct rules that assign connection tracking helpers to untrusted or unconfirmed network traffic flows. As a compensating measure, enable runtime memory error detection such as KASAN or HWASan to trap use-after-free and invalid pointer accesses when conntrack extension memory is dereferenced. These controls limit blast radius and contain exploitation, but they do not fix the underlying use-after-free vulnerability — apply the upstream patch to fully remediate.
Highest-impact CME: CME-1005 Runtime Memory Error Detection (KASAN/HWASan) (medium)
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
If the expired pointer is used in a read operation, an attacker might be able to control data read in by the application.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If the expired pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If the expired pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
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