{"id":"CVE-2026-64551","state":"PUBLISHED","title":"sctp: validate STALE_COOKIE cause length before reading staleness","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: validate STALE_COOKIE cause length before reading staleness\n\nWhen an ERROR chunk with a STALE_COOKIE cause is received in the\nCOOKIE_ECHOED state, sctp_sf_do_5_2_6_stale() reads the 4-byte Measure\nof Staleness that follows the cause header:\n\n\terr   = (struct sctp_errhdr *)(chunk->skb->data);\n\tstale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err)));\n\nerr is the first cause in the chunk, not the STALE_COOKIE cause that\ncaused the dispatch, and nothing guarantees the staleness field is\npresent. sctp_walk_errors() only requires a cause to be as long as the\n4-byte header, so for a STALE_COOKIE cause of length 4 the read runs\npast the cause, and for a minimal ERROR chunk past skb->tail. The value\nis echoed to the peer in the Cookie Preservative of the reply INIT,\nleaking uninitialized memory.\n\nsctp_sf_cookie_echoed_err() already walks to the STALE_COOKIE cause, so\ncheck its length there and pass it to sctp_sf_do_5_2_6_stale(), which\nreads that cause instead of the first one. A STALE_COOKIE cause too\nshort to hold the staleness field is discarded.\n\nThe read is reachable by any peer that can drive an association into\nCOOKIE_ECHOED, including an unprivileged process using a raw SCTP socket\nin a user and network namespace.","publishedAt":"2026-07-27T20:10:40.012Z","updatedAt":"2026-10-19T20:48:40.456Z","severity":{"score":9.1,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"6022da37786701df1fc5dd946a6dcba59d5473b1","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"861f884f5471632c731cbbd612a1c072e391a624","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"588706ebaf8cdb4a4161602949eba365514b1db1","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"a257b41ddfe9e327b26581ad2777f04b23ac73f5","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"08a8f2d13f703924316e9aeac863a88ef50990c7","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"ebe0a55d954fa8da383b6192edb8f763dcb002d5","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"bbd6b2ea966cf57b6ae095cf5a8dbc993cd197a0","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"1cd23ca80784223fa2204e16203f754da4e821f8","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sctp/sm_statefuns.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.12","versionType":"semver"},{"version":"5.10.261","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.212","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sctp/sm_statefuns.c"]}],"references":["https://git.kernel.org/stable/c/6022da37786701df1fc5dd946a6dcba59d5473b1","https://git.kernel.org/stable/c/861f884f5471632c731cbbd612a1c072e391a624","https://git.kernel.org/stable/c/588706ebaf8cdb4a4161602949eba365514b1db1","https://git.kernel.org/stable/c/a257b41ddfe9e327b26581ad2777f04b23ac73f5","https://git.kernel.org/stable/c/08a8f2d13f703924316e9aeac863a88ef50990c7","https://git.kernel.org/stable/c/ebe0a55d954fa8da383b6192edb8f763dcb002d5","https://git.kernel.org/stable/c/bbd6b2ea966cf57b6ae095cf5a8dbc993cd197a0","https://git.kernel.org/stable/c/1cd23ca80784223fa2204e16203f754da4e821f8"],"weaknesses":["CWE-125"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64551.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64551","state":"PUBLISHED","datePublished":"2026-07-27T20:10:40.012Z","dateUpdated":"2026-10-19T20:48:40.456Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T15:36:31.796Z"},"containers":{"cna":{"title":"sctp: validate STALE_COOKIE cause length before reading staleness","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: validate STALE_COOKIE cause length before reading staleness\n\nWhen an ERROR chunk with a STALE_COOKIE cause is received in the\nCOOKIE_ECHOED state, sctp_sf_do_5_2_6_stale() reads the 4-byte Measure\nof Staleness that follows the cause header:\n\n\terr   = (struct sctp_errhdr *)(chunk->skb->data);\n\tstale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err)));\n\nerr is the first cause in the chunk, not the STALE_COOKIE cause that\ncaused the dispatch, and nothing guarantees the staleness field is\npresent. sctp_walk_errors() only requires a cause to be as long as the\n4-byte header, so for a STALE_COOKIE cause of length 4 the read runs\npast the cause, and for a minimal ERROR chunk past skb->tail. The value\nis echoed to the peer in the Cookie Preservative of the reply INIT,\nleaking uninitialized memory.\n\nsctp_sf_cookie_echoed_err() already walks to the STALE_COOKIE cause, so\ncheck its length there and pass it to sctp_sf_do_5_2_6_stale(), which\nreads that cause instead of the first one. A STALE_COOKIE cause too\nshort to hold the staleness field is discarded.\n\nThe read is reachable by any peer that can drive an association into\nCOOKIE_ECHOED, including an unprivileged process using a raw SCTP socket\nin a user and network namespace."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"6022da37786701df1fc5dd946a6dcba59d5473b1","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"861f884f5471632c731cbbd612a1c072e391a624","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"588706ebaf8cdb4a4161602949eba365514b1db1","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"a257b41ddfe9e327b26581ad2777f04b23ac73f5","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"08a8f2d13f703924316e9aeac863a88ef50990c7","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"ebe0a55d954fa8da383b6192edb8f763dcb002d5","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"bbd6b2ea966cf57b6ae095cf5a8dbc993cd197a0","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"1cd23ca80784223fa2204e16203f754da4e821f8","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sctp/sm_statefuns.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.12","versionType":"semver"},{"version":"5.10.261","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.212","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sctp/sm_statefuns.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/6022da37786701df1fc5dd946a6dcba59d5473b1"},{"url":"https://git.kernel.org/stable/c/861f884f5471632c731cbbd612a1c072e391a624"},{"url":"https://git.kernel.org/stable/c/588706ebaf8cdb4a4161602949eba365514b1db1"},{"url":"https://git.kernel.org/stable/c/a257b41ddfe9e327b26581ad2777f04b23ac73f5"},{"url":"https://git.kernel.org/stable/c/08a8f2d13f703924316e9aeac863a88ef50990c7"},{"url":"https://git.kernel.org/stable/c/ebe0a55d954fa8da383b6192edb8f763dcb002d5"},{"url":"https://git.kernel.org/stable/c/bbd6b2ea966cf57b6ae095cf5a8dbc993cd197a0"},{"url":"https://git.kernel.org/stable/c/1cd23ca80784223fa2204e16203f754da4e821f8"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","baseScore":9.1,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - The vulnerable code is in the SCTP receive-side state machine and is driven entirely by an attacker-crafted ERROR chunk arriving over the network; no local access is needed. Per kernel guidance, net/ stack bugs reachable via received packets (SCTP explicitly) are Network.\nAC:L - The attacker fully controls the trigger: acting as the SCTP peer it answers INIT with INIT-ACK to place the association in COOKIE_ECHOED, then sends a minimal ERROR chunk with a 4-byte STALE_COOKIE cause as the last chunk in the packet. There is no race, no memory-layout dependency, and the vtag needed is the one the victim itself advertised in its INIT.\nPR:N - SCTP association setup is unauthenticated; the only check is sctp_vtag_verify() against a tag the peer already received in the victim's INIT. The attacker needs no credentials or privileges on the target system.\nUI:N - No human user action is required — SCTP client daemons (SIGTRAN, Diameter, cluster transports) establish and retry associations automatically, and an on-path attacker can inject the ERROR into an in-progress handshake. In the local variant an unprivileged process creates both sides itself with no user involved.\nS:U - The out-of-bounds read and the resulting disclosure stay within the kernel's own security authority; no VM, sandbox, or IOMMU boundary is crossed.\nC:H - Uninitialized kernel memory past skb->tail is read and then transmitted straight back to the attacker inside the reply INIT's Cookie Preservative parameter, and the attack can be repeated indefinitely to sample recycled network-buffer memory that may contain remnants of other connections' traffic. This is a remote, unauthenticated, repeatable kernel heap disclosure oracle, matching the C:H treatment given to the sibling SCTP uninit-read CVE-2026-53225.\nI:N - The bug is a pure read; nothing in kernel memory or in the victim's association state is modified. The only affected value is a protocol field in a packet sent to the attacker itself.\nA:H - The read runs past the end of the received packet data, a memory-safety violation whose target is not proven to remain inside the skb's allocation across all receive paths (GSO/frag_list segments, UDP-encapsulated and linearized skbs), so it can fault and oops; kernel guidance and the CNA's scoring of the equivalent SCTP out-of-bounds-read bug both treat this class as A:H."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:57:28.771Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.10.261"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.15.212"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.1.178"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.12.97"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-64551","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:42:25.961430Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-125","lang":"en","type":"CWE","description":"CWE-125 Out-of-bounds Read"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T20:48:40.456Z"}}]}}}