{"id":"CVE-2025-21972","title":"net: mctp: unshare packets when reassembling","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: mctp: unshare packets when reassembling\n\nEnsure that the frag_list used for reassembly isn't shared with other\npackets. This avoids incorrect reassembly when packe…","severity":"high","cvss":8.8,"cvssVector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 4a992bbd365094730a31bae1e12a6ca695336d57 < 3d0281d0713952e8dd14d6d47e3a9c345c28a3b7","Linux >= 4a992bbd365094730a31bae1e12a6ca695336d57 < 5c47d5bfa7b096cf8890afac32141c578583f8e0","Linux >= 4a992bbd365094730a31bae1e12a6ca695336d57 < f44fff3d3c6cd67b6f348b821d73c4d6888c7a6e","Linux >= 4a992bbd365094730a31bae1e12a6ca695336d57 < f5d83cf0eeb90fade4d5c4d17d24b8bee9ceeecc","Linux 5.15"],"published":"2025-04-01","updated":"2026-10-21","sourceUpdated":"2026-10-21T12:36:11.201Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-21972","references":[{"url":"https://git.kernel.org/stable/c/3d0281d0713952e8dd14d6d47e3a9c345c28a3b7"},{"url":"https://git.kernel.org/stable/c/5c47d5bfa7b096cf8890afac32141c578583f8e0"},{"url":"https://git.kernel.org/stable/c/f44fff3d3c6cd67b6f348b821d73c4d6888c7a6e"},{"url":"https://git.kernel.org/stable/c/f5d83cf0eeb90fade4d5c4d17d24b8bee9ceeecc"}],"tags":["cve.org"],"epss":0.00302,"epssPercentile":0.22778,"ingestedAt":"2026-10-21T12:48:53.716Z","slug":"CVE-2025-21972","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet: mctp: unshare packets when reassembling\n\nEnsure that the frag_list used for reassembly isn't shared with other\npackets. This avoids incorrect reassembly when packets are cloned, and\nprevents a memory leak due to circular references between fragments and\ntheir skb_shared_info.\n\nThe upcoming MCTP-over-USB driver uses skb_clone which can trigger the\nproblem - other MCTP drivers don't share SKBs.\n\nA kunit test is added to reproduce the issue.\n\n## Affected\n\n- `Linux >= 4a992bbd365094730a31bae1e12a6ca695336d57 < 3d0281d0713952e8dd14d6d47e3a9c345c28a3b7`\n- `Linux >= 4a992bbd365094730a31bae1e12a6ca695336d57 < 5c47d5bfa7b096cf8890afac32141c578583f8e0`\n- `Linux >= 4a992bbd365094730a31bae1e12a6ca695336d57 < f44fff3d3c6cd67b6f348b821d73c4d6888c7a6e`\n- `Linux >= 4a992bbd365094730a31bae1e12a6ca695336d57 < f5d83cf0eeb90fade4d5c4d17d24b8bee9ceeecc`\n- `Linux 5.15`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":48.4,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}