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

> A double free vulnerability in the Linux kernel rtase driver allows attackers to cause denial of service or potentially execute code via crafted network packets.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-74545, DEBIAN-CVE-2026-74545, GHSA-v487-w46v-372v, UBUNTU-CVE-2026-74545

## What is CVE-2026-74545?

CVE-2026-74545 is a critical memory corruption vulnerability in Linux, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

## Which versions are affected by CVE-2026-74545?


## How do I fix CVE-2026-74545?

Apply the vendor's patch.

## Is CVE-2026-74545 being exploited?

There is no known exploitation of CVE-2026-74545 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74545 and fix it if it is affected.

What it is: CVE-2026-74545 is a critical memory corruption vulnerability in Linux, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-74545 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-74545/ (Markdown: https://insights.sbomify.com/CVE-2026-74545/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74545
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74545
- OSV: https://osv.dev/vulnerability/CVE-2026-74545

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74545/
Summaries are generated and may contain mistakes; the official description above is the record.