{"id":"CVE-2026-97985","state":"PUBLISHED","title":"af_unix: Update last skb marker in manage_oob().","description":"In the Linux kernel, the following vulnerability has been resolved:\n\naf_unix: Update last skb marker in manage_oob().\n\nFahad Alharbi reported that blocking recv(MSG_PEEK) could hog CPU\ndue to OOB skb.\n\nIn the following cases, manage_oob() skips OOB skb(s) and returns\nNULL for the last recv(MSG_PEEK):\n\n  socketpair(AF_UNIX, SOCK_STREAM, 0, sk);\n\n  1) skb -> OOB skb -> NULL\n     send(sk[0], \"ab\", 2, MSG_OOB);\n     recv(sk[1], buf, 0, MSG_PEEK);\n\n  2) skb -> consumed OOB skb -> NULL\n     send(sk[0], \"ab\", 2, MSG_OOB);\n     recv(sk[1], buf, 1, MSG_OOB);\n     recv(sk[1], buf, 0, MSG_PEEK);\n\n  3) consumed OOB skb -> OOB skb -> NULL\n     send(sk[0], \"a\", 1, MSG_OOB);\n     recv(sk[1], buf, 0, MSG_OOB);\n     send(sk[0], \"b\", 1, MSG_OOB);\n     recv(sk[1], buf, 1, MSG_PEEK);\n\nThen, @copied is 0 in unix_stream_read_generic() (zero-length buffer,\nor non-OOB skb is not yet consumed), and unix_stream_data_wait() is\ncalled.\n\nHowever, it returns immediately because @last is not updated in\nunix_stream_read_generic(), and the thread busy-waits for a new skb.\n\nLet's update @last in manage_oob().\n\nFor MSG_PEEK, @last is updated with the skipped OOB, and for the\nnon-peek case, @last matches the returned value (when !copied)\nbecause OOB is unlinked.\n\nNote that manage_oob() is inlined and no stack canary is added.","publishedAt":"2026-09-25T10:23:20.173Z","updatedAt":"2026-10-21T12:53:57.548Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"022d81a709cd553bbe2db8675f8e824f4aee6284","status":"affected","lessThan":"bd91dc313afe21e9d6b31ca6a47606a33ca5e35c","versionType":"git"},{"version":"22dd70eb2c3d754862964377a75abafd3167346b","status":"affected","lessThan":"0630bfc773d85ac44da05b2c5a037dbbd39301ab","versionType":"git"},{"version":"22dd70eb2c3d754862964377a75abafd3167346b","status":"affected","lessThan":"f1816b3d7ce80dcf086bb68ff5ae6e09520ca1fa","versionType":"git"},{"version":"22dd70eb2c3d754862964377a75abafd3167346b","status":"affected","lessThan":"fc62a26493a98a0424d9dae2eb92a1daa1321f65","versionType":"git"},{"version":"22dd70eb2c3d754862964377a75abafd3167346b","status":"affected","lessThan":"94fd4debd2e3a69cf93e766c8b328a810c228119","versionType":"git"},{"version":"ae3f9e1221b31b18dbd4c4b85d08574996bbd973","status":"affected","versionType":"git"},{"version":"ba0db4638525b8b054b3d546b45f7e473f477027","status":"affected","versionType":"git"},{"version":"16dc252e7007547a7b72a2c21022ef81fb45e6a3","status":"affected","versionType":"git"},{"version":"6.6.29","status":"affected","lessThan":"6.6.160","versionType":"semver"},{"version":"5.15.157","status":"affected","lessThan":"5.16","versionType":"semver"},{"version":"6.1.88","status":"affected","lessThan":"6.2","versionType":"semver"},{"version":"6.8.8","status":"affected","lessThan":"6.9","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/unix/af_unix.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.9","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.111","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.53","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.7","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/unix/af_unix.c"]}],"references":["https://git.kernel.org/stable/c/bd91dc313afe21e9d6b31ca6a47606a33ca5e35c","https://git.kernel.org/stable/c/0630bfc773d85ac44da05b2c5a037dbbd39301ab","https://git.kernel.org/stable/c/f1816b3d7ce80dcf086bb68ff5ae6e09520ca1fa","https://git.kernel.org/stable/c/fc62a26493a98a0424d9dae2eb92a1daa1321f65","https://git.kernel.org/stable/c/94fd4debd2e3a69cf93e766c8b328a810c228119"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/97xxx/CVE-2026-97985.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-97985","state":"PUBLISHED","datePublished":"2026-09-25T10:23:20.173Z","dateUpdated":"2026-10-21T12:53:57.548Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:18:58.208Z"},"containers":{"cna":{"title":"af_unix: Update last skb marker in manage_oob().","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\naf_unix: Update last skb marker in manage_oob().\n\nFahad Alharbi reported that blocking recv(MSG_PEEK) could hog CPU\ndue to OOB skb.\n\nIn the following cases, manage_oob() skips OOB skb(s) and returns\nNULL for the last recv(MSG_PEEK):\n\n  socketpair(AF_UNIX, SOCK_STREAM, 0, sk);\n\n  1) skb -> OOB skb -> NULL\n     send(sk[0], \"ab\", 2, MSG_OOB);\n     recv(sk[1], buf, 0, MSG_PEEK);\n\n  2) skb -> consumed OOB skb -> NULL\n     send(sk[0], \"ab\", 2, MSG_OOB);\n     recv(sk[1], buf, 1, MSG_OOB);\n     recv(sk[1], buf, 0, MSG_PEEK);\n\n  3) consumed OOB skb -> OOB skb -> NULL\n     send(sk[0], \"a\", 1, MSG_OOB);\n     recv(sk[1], buf, 0, MSG_OOB);\n     send(sk[0], \"b\", 1, MSG_OOB);\n     recv(sk[1], buf, 1, MSG_PEEK);\n\nThen, @copied is 0 in unix_stream_read_generic() (zero-length buffer,\nor non-OOB skb is not yet consumed), and unix_stream_data_wait() is\ncalled.\n\nHowever, it returns immediately because @last is not updated in\nunix_stream_read_generic(), and the thread busy-waits for a new skb.\n\nLet's update @last in manage_oob().\n\nFor MSG_PEEK, @last is updated with the skipped OOB, and for the\nnon-peek case, @last matches the returned value (when !copied)\nbecause OOB is unlinked.\n\nNote that manage_oob() is inlined and no stack canary is added."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"022d81a709cd553bbe2db8675f8e824f4aee6284","status":"affected","lessThan":"bd91dc313afe21e9d6b31ca6a47606a33ca5e35c","versionType":"git"},{"version":"22dd70eb2c3d754862964377a75abafd3167346b","status":"affected","lessThan":"0630bfc773d85ac44da05b2c5a037dbbd39301ab","versionType":"git"},{"version":"22dd70eb2c3d754862964377a75abafd3167346b","status":"affected","lessThan":"f1816b3d7ce80dcf086bb68ff5ae6e09520ca1fa","versionType":"git"},{"version":"22dd70eb2c3d754862964377a75abafd3167346b","status":"affected","lessThan":"fc62a26493a98a0424d9dae2eb92a1daa1321f65","versionType":"git"},{"version":"22dd70eb2c3d754862964377a75abafd3167346b","status":"affected","lessThan":"94fd4debd2e3a69cf93e766c8b328a810c228119","versionType":"git"},{"version":"ae3f9e1221b31b18dbd4c4b85d08574996bbd973","status":"affected","versionType":"git"},{"version":"ba0db4638525b8b054b3d546b45f7e473f477027","status":"affected","versionType":"git"},{"version":"16dc252e7007547a7b72a2c21022ef81fb45e6a3","status":"affected","versionType":"git"},{"version":"6.6.29","status":"affected","lessThan":"6.6.160","versionType":"semver"},{"version":"5.15.157","status":"affected","lessThan":"5.16","versionType":"semver"},{"version":"6.1.88","status":"affected","lessThan":"6.2","versionType":"semver"},{"version":"6.8.8","status":"affected","lessThan":"6.9","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/unix/af_unix.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.9","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.111","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.53","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.7","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/unix/af_unix.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/bd91dc313afe21e9d6b31ca6a47606a33ca5e35c"},{"url":"https://git.kernel.org/stable/c/0630bfc773d85ac44da05b2c5a037dbbd39301ab"},{"url":"https://git.kernel.org/stable/c/f1816b3d7ce80dcf086bb68ff5ae6e09520ca1fa"},{"url":"https://git.kernel.org/stable/c/fc62a26493a98a0424d9dae2eb92a1daa1321f65"},{"url":"https://git.kernel.org/stable/c/94fd4debd2e3a69cf93e766c8b328a810c228119"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-21T12:53:57.548Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.29","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"6.12.111"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"6.18.53"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"7.2.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"7.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.88"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8.8"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}