{"id":"CVE-2026-98525","state":"PUBLISHED","title":"mctp: route: iterate socket tag list in mctp_lookup_prealloc_tag()","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).","publishedAt":"2026-10-18T15:17:43.216Z","updatedAt":"2026-10-19T09:21:07.010Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"63ed1aab3d40aa61aaa66819bdce9377ac7f40fa","status":"affected","lessThan":"09299addab11857e92eca55cd8ef3350b927c90c","versionType":"git"},{"version":"63ed1aab3d40aa61aaa66819bdce9377ac7f40fa","status":"affected","lessThan":"e35cb500dd14882f8dee61783fccd1823fd3ab0d","versionType":"git"},{"version":"63ed1aab3d40aa61aaa66819bdce9377ac7f40fa","status":"affected","lessThan":"f178300e2f56ca9ec2a3a0090608730bbee0af7b","versionType":"git"},{"version":"63ed1aab3d40aa61aaa66819bdce9377ac7f40fa","status":"affected","lessThan":"26cc0e69cce062cd3aa6fae33074684669c35a71","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/mctp/route.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.18","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","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/mctp/route.c"]}],"references":["https://git.kernel.org/stable/c/09299addab11857e92eca55cd8ef3350b927c90c","https://git.kernel.org/stable/c/e35cb500dd14882f8dee61783fccd1823fd3ab0d","https://git.kernel.org/stable/c/f178300e2f56ca9ec2a3a0090608730bbee0af7b","https://git.kernel.org/stable/c/26cc0e69cce062cd3aa6fae33074684669c35a71"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98525.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98525","state":"PUBLISHED","datePublished":"2026-10-18T15:17:43.216Z","dateUpdated":"2026-10-19T09:21:07.010Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.355Z"},"containers":{"cna":{"title":"mctp: route: iterate socket tag list in mctp_lookup_prealloc_tag()","descriptions":[{"lang":"en","value":"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)."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"63ed1aab3d40aa61aaa66819bdce9377ac7f40fa","status":"affected","lessThan":"09299addab11857e92eca55cd8ef3350b927c90c","versionType":"git"},{"version":"63ed1aab3d40aa61aaa66819bdce9377ac7f40fa","status":"affected","lessThan":"e35cb500dd14882f8dee61783fccd1823fd3ab0d","versionType":"git"},{"version":"63ed1aab3d40aa61aaa66819bdce9377ac7f40fa","status":"affected","lessThan":"f178300e2f56ca9ec2a3a0090608730bbee0af7b","versionType":"git"},{"version":"63ed1aab3d40aa61aaa66819bdce9377ac7f40fa","status":"affected","lessThan":"26cc0e69cce062cd3aa6fae33074684669c35a71","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/mctp/route.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.18","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","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/mctp/route.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/09299addab11857e92eca55cd8ef3350b927c90c"},{"url":"https://git.kernel.org/stable/c/e35cb500dd14882f8dee61783fccd1823fd3ab0d"},{"url":"https://git.kernel.org/stable/c/f178300e2f56ca9ec2a3a0090608730bbee0af7b"},{"url":"https://git.kernel.org/stable/c/26cc0e69cce062cd3aa6fae33074684669c35a71"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T09:21:07.010Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.12.112"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.18.55"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"7.2.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}