CVE-2026-80850
Description
A flaw was found in the Linux kernel's TCP Authentication Option (TCP-AO) implementation. An unprivileged local attacker could exploit a race condition when a network device is detached from its Virtual Routing and Forwarding (VRF) interface. This could lead to a use-after-free vulnerability, causing a system crash and resulting in a Denial of Service (DoS).
Statement
A use-after-free vulnerability in the Linux kernel's TCP Authentication Option (TCP-AO) implementation, rated IMPORTANT by Red Hat Product Security with a Red Hat CVSS 3.1 score of 7.0 (AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H). When TCP-AO is configured on a socket, a race condition between connection establishment and detaching the bound network device from its Virtual Routing and Forwarding (VRF) interface can make tcp_ao_connect_init() remove the only matching AO key and directly free the socket's AO information while the receive path can still access the freed structure under RCU, resulting in a use-after-free write in tcp_inbound_ao_hash(). An unprivileged local attacker able to create user and network namespaces could win this race by racing connect() against detaching a device from its VRF while TCP-AO traffic is processed, crashing the kernel and causing a denial of service; exploitation requires winning a narrow timing race, reflected in the high attack complexity of the CVSS score. In Red Hat Enterprise Linux 9.10, the kernel and kernel-rt packages are affected and a fix is being pursued for that stream. The other Red Hat Enterprise Linux versions and update streams, the Red Hat In-Vehicle OS releases, and the OpenShift Container Platform releases covered by this flaw are not affected because the vulnerable code is not present in their shipped kernels.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
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 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | High | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | High | N/A | N/A |
| Integrity Impact | High | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/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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