CVE-2026-31674
Description
A flaw was found in the Linux kernel's netfilter subsystem, specifically within the ip6t_rt module. This vulnerability occurs when processing IPv6 routing header (RT) match rules with an oversized address number (addrnr). A local attacker could exploit this by crafting a malicious netfilter rule, leading to an out-of-bounds memory access. This could result in a denial of service, causing the system to crash or become unresponsive.
Statement
IPv6 routing-header match parsing now rejects oversized addrnr, preventing skb overruns in rt_mt6_check(). Red Hat recommends updated kernels on hosts using ip6tables RT matches.
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 | 5.5 | N/A | 7.1 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Understanding the Weakness (CWE)
Other,Integrity,Availability
Technical Impact: Varies by Context; DoS: Resource Consumption (CPU); Modify Memory; Read Memory
When the quantity is not properly validated, then attackers can specify malicious quantities to cause excessive resource allocation, trigger unexpected failures, enable buffer overflows, etc.
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