{"id":"CVE-2026-97985","published":"2026-09-25T11:17:26.560","lastModified":"2026-09-25T11:17:26.560","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.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/0630bfc773d85ac44da05b2c5a037dbbd39301ab","tags":[]},{"url":"https://git.kernel.org/stable/c/94fd4debd2e3a69cf93e766c8b328a810c228119","tags":[]},{"url":"https://git.kernel.org/stable/c/f1816b3d7ce80dcf086bb68ff5ae6e09520ca1fa","tags":[]},{"url":"https://git.kernel.org/stable/c/fc62a26493a98a0424d9dae2eb92a1daa1321f65","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}