{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-63971", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T07:54:57.024Z", "datePublished": "2026-07-19T14:55:57.792Z", "dateUpdated": "2026-08-05T12:37:42.789Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:37:42.789Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: fix race between sctp_wait_for_connect and peeloff\n\nsctp_wait_for_connect() drops and re-acquires the socket lock while\nwaiting for the association to reach ESTABLISHED state. During this\nwindow, another thread can peeloff the association to a new socket via\ngetsockopt(SCTP_SOCKOPT_PEELOFF), changing asoc->base.sk. After\nre-acquiring the old socket lock, sctp_wait_for_connect() returns\nsuccess without noticing the migration — the caller then accesses\nthe association under the wrong lock in sctp_datamsg_from_user().\n\nAdd the same sk != asoc->base.sk check that sctp_wait_for_sndbuf()\nalready has, returning an error if the association was migrated while\nwe slept." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - Exploitation requires local syscalls on an SCTP socket (`sendmsg`/`sendto` to trigger `sctp_wait_for_connect`, and `getsockopt(SCTP_SOCKOPT_PEELOFF)` to peel off the association). A remote peer can only help complete the SCTP handshake; it cannot invoke peeloff or the racing send path.\nAC:L - The attacker controls both sides of the race by running concurrent threads on the same SCTP one-to-many socket, timing peeloff during the window where `sctp_wait_for_connect()` has released the socket lock. Required options (`SCTP_FRAGMENT_INTERLEAVE`, `SCTP_INTERLEAVING_SUPPORTED`, and `net.sctp.intl_enable`) are attacker-settable in a user/net namespace.\nPR:L - No real-root capability is required; an unprivileged user can create SCTP sockets and drive the full race from a user namespace (`unshare -Urn`), including enabling `net.sctp.intl_enable` and the interleaving socket options needed to reach the vulnerable `sctp_sendmsg_to_asoc()` path.\nUI:N - Exploitation is fully attacker-driven through coordinated local threads and does not require any action from a victim user or administrator beyond normal SCTP socket use.\nS:U - Impact is confined to kernel memory integrity/availability within the same security authority; successful exploitation would be local privilege escalation, not a cross-boundary escape such as VM or container breakout by itself.\nC:H - After peeloff migrates `asoc->base.sk`, the caller continues in `sctp_datamsg_from_user()` while holding the wrong socket lock, creating unsynchronized concurrent access to association/stream state that can corrupt kernel heap metadata and be leveraged for arbitrary kernel memory disclosure.\nI:H - The post-race path builds and queues DATA/I-DATA chunks via `sctp_datamsg_from_user()` and `sctp_primitive_SEND()` without the correct socket lock, enabling concurrent modification of association output queues and stream structures that can be turned into arbitrary kernel writes or control-flow hijacking.\nA:H - Concurrent unsynchronized access to a live SCTP association after peeloff can cause kernel oops/panic or wedged associations, and the underlying race is a classic kernel concurrency defect with high availability impact even before full exploitation." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sctp/socket.c" ], "versions": [ { "version": "668c9beb9020d5834ee9e43c208190a07d2b1928", "lessThan": "0e0d5bc76fd4267a71334fcc8f1a5fbcf997845d", "status": "affected", "versionType": "git" }, { "version": "668c9beb9020d5834ee9e43c208190a07d2b1928", "lessThan": "bcfeac79af740735ace44008b4a11b8e5add20f5", "status": "affected", "versionType": "git" }, { "version": "668c9beb9020d5834ee9e43c208190a07d2b1928", "lessThan": "8e9b56051d24540cfbf39194618708c4a7633549", "status": "affected", "versionType": "git" }, { "version": "668c9beb9020d5834ee9e43c208190a07d2b1928", "lessThan": "634a9af8a26a84d8b0d7b3b643204b344b42d9fb", "status": "affected", "versionType": "git" }, { "version": "668c9beb9020d5834ee9e43c208190a07d2b1928", "lessThan": "7d2038d4b80166f7bead8d07eba3b97405816c21", "status": "affected", "versionType": "git" }, { "version": "668c9beb9020d5834ee9e43c208190a07d2b1928", "lessThan": "68667ee4c7dadf7f63167234e2a1af09b3f7874e", "status": "affected", "versionType": "git" }, { "version": "668c9beb9020d5834ee9e43c208190a07d2b1928", "lessThan": "6140cfa721451fa6e18e134e709703c2bf34d0fb", "status": "affected", "versionType": "git" }, { "version": "668c9beb9020d5834ee9e43c208190a07d2b1928", "lessThan": "f14fe6395a8b3d961a61e138ad7b36ba3626dd4e", "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/socket.c" ], "versions": [ { "version": "4.16", "status": "affected" }, { "version": "0", "lessThan": "4.16", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.259", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.210", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.176", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.143", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.93", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.35", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.12", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1", "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": "4.16", "versionEndExcluding": "5.10.259" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "5.15.210" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.1.176" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.6.143" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.12.93" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.18.35" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "7.0.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "7.1" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/0e0d5bc76fd4267a71334fcc8f1a5fbcf997845d" }, { "url": "https://git.kernel.org/stable/c/bcfeac79af740735ace44008b4a11b8e5add20f5" }, { "url": "https://git.kernel.org/stable/c/8e9b56051d24540cfbf39194618708c4a7633549" }, { "url": "https://git.kernel.org/stable/c/634a9af8a26a84d8b0d7b3b643204b344b42d9fb" }, { "url": "https://git.kernel.org/stable/c/7d2038d4b80166f7bead8d07eba3b97405816c21" }, { "url": "https://git.kernel.org/stable/c/68667ee4c7dadf7f63167234e2a1af09b3f7874e" }, { "url": "https://git.kernel.org/stable/c/6140cfa721451fa6e18e134e709703c2bf34d0fb" }, { "url": "https://git.kernel.org/stable/c/f14fe6395a8b3d961a61e138ad7b36ba3626dd4e" } ], "title": "sctp: fix race between sctp_wait_for_connect and peeloff", "x_generator": { "engine": "bippy-1.2.0" } } } }