{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40240", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.181Z", "datePublished": "2025-12-04T15:31:29.715Z", "dateUpdated": "2026-08-05T12:08:44.117Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:08:44.117Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: avoid NULL dereference when chunk data buffer is missing\n\nchunk->skb pointer is dereferenced in the if-block where it's supposed\nto be NULL only.\n\nchunk->skb can only be NULL if chunk->head_skb is not. Check for frag_list\ninstead and do it just before replacing chunk->skb. We're sure that\notherwise chunk->skb is non-NULL because of outer if() condition." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - The bug is in the SCTP packet input path (`sctp_rcv` → `sctp_inq_push` → `sctp_assoc_bh_rcv` → `sctp_inq_pop`), processing chunk data supplied by a peer over IP; the vulnerable component is bound to the network stack and is driven entirely by received SCTP packets, including from a container/veth peer on the other side of a security boundary.\nAC:L - The trigger is a re-read of `skb_shinfo(skb)->frag_list` on a shared/cloned GSO skb, and the attacker controls both sides — generating the large GSO SCTP packets and the concurrent clone/consumer that mutates the shared shinfo — which is exactly the pattern syzbot reproduced for the sibling bug in the same lines of `sctp_inq_pop()`.\nPR:N - `sctp_inq_pop()` runs before any chunk is validated by the state machine — OOTB packets and INIT chunks from a completely unauthenticated peer reach it, and no capability or credential check exists anywhere on the `sctp_rcv()` path.\nUI:N - Processing happens automatically in softirq/backlog context as soon as the packets are received; no victim action of any kind is needed.\nS:U - The NULL dereference faults inside the kernel's own SCTP receive processing; no hypervisor, IOMMU, or sandbox boundary is crossed.\nC:N - The fault is a read of an unmapped low address (`NULL->dev`) that immediately oopses; no attacker-controlled memory is read back or returned to userspace.\nI:N - Nothing is written — the bug is a read of a NULL pointer field, so no kernel memory is modified and no control-flow hijack primitive is produced.\nA:H - The path first hits `WARN_ON()` (an immediate panic on `panic_on_warn=1` systems, common on hardened/cloud kernels) and then dereferences NULL, producing a kernel oops in softirq/backlog context that kills SCTP receive processing and typically brings down the machine; it is repeatable by simply resending traffic." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sctp/inqueue.c" ], "versions": [ { "version": "90017accff61ae89283ad9a51f9ac46ca01633fb", "lessThan": "61cda2777b07d27459f5cac5a047c3edf9c8a1a9", "status": "affected", "versionType": "git" }, { "version": "90017accff61ae89283ad9a51f9ac46ca01633fb", "lessThan": "08165c296597075763130919f2aae59b5822f016", "status": "affected", "versionType": "git" }, { "version": "90017accff61ae89283ad9a51f9ac46ca01633fb", "lessThan": "03e80a4b04ef1fb2c61dd63216ab8d3a5dcb196f", "status": "affected", "versionType": "git" }, { "version": "90017accff61ae89283ad9a51f9ac46ca01633fb", "lessThan": "4f6da435fb5d8a21cbf8cae5ca5a2ba0e1012b71", "status": "affected", "versionType": "git" }, { "version": "90017accff61ae89283ad9a51f9ac46ca01633fb", "lessThan": "cb9055ba30306ede4ad920002233d0659982f1cb", "status": "affected", "versionType": "git" }, { "version": "90017accff61ae89283ad9a51f9ac46ca01633fb", "lessThan": "7a832b0f99be19df608cb75c023f8027b1789bd1", "status": "affected", "versionType": "git" }, { "version": "90017accff61ae89283ad9a51f9ac46ca01633fb", "lessThan": "89b465b54227c245ddc7cc9ed822231af21123ef", "status": "affected", "versionType": "git" }, { "version": "90017accff61ae89283ad9a51f9ac46ca01633fb", "lessThan": "441f0647f7673e0e64d4910ef61a5fb8f16bfb82", "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/inqueue.c" ], "versions": [ { "version": "4.8", "status": "affected" }, { "version": "0", "lessThan": "4.8", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.301", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.246", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.196", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.158", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.115", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.56", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.6", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18", "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": "4.8", "versionEndExcluding": "5.4.301" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "5.10.246" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "5.15.196" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.1.158" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.6.115" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.12.56" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.17.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.18" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/61cda2777b07d27459f5cac5a047c3edf9c8a1a9" }, { "url": "https://git.kernel.org/stable/c/08165c296597075763130919f2aae59b5822f016" }, { "url": "https://git.kernel.org/stable/c/03e80a4b04ef1fb2c61dd63216ab8d3a5dcb196f" }, { "url": "https://git.kernel.org/stable/c/4f6da435fb5d8a21cbf8cae5ca5a2ba0e1012b71" }, { "url": "https://git.kernel.org/stable/c/cb9055ba30306ede4ad920002233d0659982f1cb" }, { "url": "https://git.kernel.org/stable/c/7a832b0f99be19df608cb75c023f8027b1789bd1" }, { "url": "https://git.kernel.org/stable/c/89b465b54227c245ddc7cc9ed822231af21123ef" }, { "url": "https://git.kernel.org/stable/c/441f0647f7673e0e64d4910ef61a5fb8f16bfb82" } ], "title": "sctp: avoid NULL dereference when chunk data buffer is missing", "x_generator": { 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