CVE-2026-46331
Description
A flaw was found in the Linux kernel's traffic control packet editing (pedit) subsystem. In tcf_pedit_act(), the copy-on-write (COW) range for skb_ensure_writable() is computed once before iterating over edit keys, but the calculation does not account for runtime header offsets added by typed keys. This can leave part of the target write region without a proper copy-on-write, leading to an out-of-bounds write that corrupts page cache memory. A local attacker with the ability to configure traffic control rules could exploit this to escalate privileges or crash the system.
Security Bulletin
Statement
Red Hat rates this flaw as Important severity.
This vulnerability is in the kernel's traffic control (tc) pedit action, which requires CAP_NET_ADMIN capability to configure. By default in Red Hat Enterprise Linux, this limits exploitation to the root user or processes explicitly granted network administration capabilities. However, in some circumstances unprivileged users may obtain CAP_NET_ADMIN within user namespaces. Successful exploitation could lead to arbitrary code execution in kernel context or a system crash.
Red Hat Enterprise Linux 7 and earlier are not affected. Within OpenShift Container Platform, the vulnerable module is not loaded by default, reducing the severity to Low.
Mitigation
See the security bulletin for a detailed mitigation procedure.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.7 | N/A | 6.7 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | High | N/A | High |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
Frequently Asked Questions
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