{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64551", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.796Z", "datePublished": "2026-07-27T20:10:40.012Z", "dateUpdated": "2026-08-17T04:57:28.771Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:57:28.771Z" }, "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." } ], "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sctp/sm_statefuns.c" ], "versions": [ { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "6022da37786701df1fc5dd946a6dcba59d5473b1", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "861f884f5471632c731cbbd612a1c072e391a624", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "588706ebaf8cdb4a4161602949eba365514b1db1", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "a257b41ddfe9e327b26581ad2777f04b23ac73f5", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "08a8f2d13f703924316e9aeac863a88ef50990c7", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "ebe0a55d954fa8da383b6192edb8f763dcb002d5", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "bbd6b2ea966cf57b6ae095cf5a8dbc993cd197a0", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "1cd23ca80784223fa2204e16203f754da4e821f8", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sctp/sm_statefuns.c" ], "versions": [ { "version": "2.6.12", "status": "affected" }, { "version": "0", "lessThan": "2.6.12", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.261", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.212", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "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" } ] } ] } ], "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" } ], "title": "sctp: validate STALE_COOKIE cause length before reading staleness", "x_generator": { "engine": "bippy-1.2.0" } } } }