net: mctp: unshare packets when reassembling
CVE-2025-21972 · published 1 Apr 2025
How serious is it
- Severity: high, CVSS score 8.8 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2025-21972?
Paste this prompt into Claude Code, Cursor or any AI coding tool: it runs a free Shippable scan of your project and fixes what it finds. Built with Lovable, Bolt or v0? Scan your live app. Or upload your package file.
Who is affected
- Linux Linux: 4a992bbd365094730a31bae1e12a6ca695336d57 to < 3d0281d0713952e8dd14d6d47e3a9c345c28a3b7, 4a992bbd365094730a31bae1e12a6ca695336d57 to < 5c47d5bfa7b096cf8890afac32141c578583f8e0, 4a992bbd365094730a31bae1e12a6ca695336d57 to < f44fff3d3c6cd67b6f348b821d73c4d6888c7a6e, 4a992bbd365094730a31bae1e12a6ca695336d57 to < f5d83cf0eeb90fade4d5c4d17d24b8bee9ceeecc
- Linux Linux: 5.15
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
In the Linux kernel, the following vulnerability has been resolved:
net: mctp: unshare packets when reassembling
Ensure that the frag_list used for reassembly isn't shared with other
packets. This avoids incorrect reassembly when packets are cloned, and
prevents a memory leak due to circular references between fragments and
their skb_shared_info.
The upcoming MCTP-over-USB driver uses skb_clone which can trigger the
problem - other MCTP drivers don't share SKBs.
A kunit test is added to reproduce the issue.
Check your whole app
Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.
References
- git.kernel.org/stable/c/3d0281d0713952e8dd14d6d47e3a9c345c28a3b7
- git.kernel.org/stable/c/5c47d5bfa7b096cf8890afac32141c578583f8e0
- git.kernel.org/stable/c/f44fff3d3c6cd67b6f348b821d73c4d6888c7a6e
- git.kernel.org/stable/c/f5d83cf0eeb90fade4d5c4d17d24b8bee9ceeecc
Merged from CVE List. Last updated 25 Oct 2026. All vulnerabilities · RSS · JSON