{"id":"CVE-2026-98525","published":"2026-10-18T16:17:03.953","lastModified":"2026-10-19T10:19:07.707","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmctp: route: iterate socket tag list in mctp_lookup_prealloc_tag()\n\nWhen a socket transmits a packet with MCTP_TAG_PREALLOC set,\nmctp_lookup_prealloc_tag() iterates over the per-netns &mns->keys list\nand matches netid, req_tag, peer_addr, and manual_alloc, without\nchecking whether tmp->sk == &msk->sk. This allows any MCTP socket in the\nsame network namespace to use and consume another socket's preallocated\ntag.\n\nIterate the socket's own tag list (&msk->keys via sklist) instead of the\nnamespace-wide &mns->keys list in mctp_lookup_prealloc_tag(), ensuring\nthat only tags allocated by msk are matched.\n\nTested in QEMU against Linux 7.3.0-rc3 by allocating a manual tag\n(0x18) on socket A via SIOCMCTPALLOCTAG for peer EID 9 and sending a\n4-byte message with MCTP_TAG_PREALLOC from socket B in the same network\nnamespace. On the unfixed kernel, sendto(sock_b) using socket A's\npreallocated tag succeeds (ret = 4); with this patch applied,\nsendto(sock_b) fails with -ENOENT (errno = 2) while sendto(sock_a)\nsucceeds (ret = 4).","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/09299addab11857e92eca55cd8ef3350b927c90c","tags":[]},{"url":"https://git.kernel.org/stable/c/26cc0e69cce062cd3aa6fae33074684669c35a71","tags":[]},{"url":"https://git.kernel.org/stable/c/e35cb500dd14882f8dee61783fccd1823fd3ab0d","tags":[]},{"url":"https://git.kernel.org/stable/c/f178300e2f56ca9ec2a3a0090608730bbee0af7b","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}