CVE-2025-21972

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux4a992bbd365094730a31bae1e12a6ca695336d57 < 5c47d5bfa7b096cf8890afac32141c578583f8e0affected
LinuxLinux4a992bbd365094730a31bae1e12a6ca695336d57 < f44fff3d3c6cd67b6f348b821d73c4d6888c7a6eaffected
LinuxLinux4a992bbd365094730a31bae1e12a6ca695336d57 < f5d83cf0eeb90fade4d5c4d17d24b8bee9ceeeccaffected
LinuxLinux5.15affected
LinuxLinux0 < 5.15unaffected
LinuxLinux6.12.20 <= 6.12.*unaffected
LinuxLinux6.13.8 <= 6.13.*unaffected
LinuxLinux6.14 <= *unaffected

Weaknesses

References