CVE-2025-21972

net: mctp: unshare packets when reassembling

Description

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.

N/A

CVSS

Severity:

EPSS 0.03%

Affected: Linux Linux

References

Link	Tags
https://git.kernel.org/stable/c/5c47d5bfa7b096cf8890afac32141c578583f8e0
https://git.kernel.org/stable/c/f44fff3d3c6cd67b6f348b821d73c4d6888c7a6e
https://git.kernel.org/stable/c/f5d83cf0eeb90fade4d5c4d17d24b8bee9ceeecc

Frequently Asked Questions

What is the severity of CVE-2025-21972?: CVE-2025-21972 has not yet been assigned a CVSS score.
How to fix CVE-2025-21972?: To fix CVE-2025-21972, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2025-21972 being actively exploited in the wild?: As for now, there are no information to confirm that CVE-2025-21972 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-21972?: CVE-2025-21972 affects Linux Linux, Linux Linux.

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