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CVE-2025-40240 (GCVE-0-2025-40240)

Vulnerability from cvelistv5 – Published: 2025-12-04 15:31 – Updated: 2026-08-05 12:08
VLAI
Title
sctp: avoid NULL dereference when chunk data buffer is missing
Summary
In the Linux kernel, the following vulnerability has been resolved: sctp: avoid NULL dereference when chunk data buffer is missing chunk->skb pointer is dereferenced in the if-block where it's supposed to be NULL only. chunk->skb can only be NULL if chunk->head_skb is not. Check for frag_list instead and do it just before replacing chunk->skb. We're sure that otherwise chunk->skb is non-NULL because of outer if() condition.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-16 19:41 UTC
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 90017accff61ae89283ad9a51f9ac46ca01633fb , < 61cda2777b07d27459f5cac5a047c3edf9c8a1a9 (git)
Affected: 90017accff61ae89283ad9a51f9ac46ca01633fb , < 08165c296597075763130919f2aae59b5822f016 (git)
Affected: 90017accff61ae89283ad9a51f9ac46ca01633fb , < 03e80a4b04ef1fb2c61dd63216ab8d3a5dcb196f (git)
Affected: 90017accff61ae89283ad9a51f9ac46ca01633fb , < 4f6da435fb5d8a21cbf8cae5ca5a2ba0e1012b71 (git)
Affected: 90017accff61ae89283ad9a51f9ac46ca01633fb , < cb9055ba30306ede4ad920002233d0659982f1cb (git)
Affected: 90017accff61ae89283ad9a51f9ac46ca01633fb , < 7a832b0f99be19df608cb75c023f8027b1789bd1 (git)
Affected: 90017accff61ae89283ad9a51f9ac46ca01633fb , < 89b465b54227c245ddc7cc9ed822231af21123ef (git)
Affected: 90017accff61ae89283ad9a51f9ac46ca01633fb , < 441f0647f7673e0e64d4910ef61a5fb8f16bfb82 (git)
guessed Create a notification for this product.
Linux Linux Affected: 4.8
Unaffected: 0 , < 4.8 (semver)
Unaffected: 5.4.301 , ≤ 5.4.* (semver)
Unaffected: 5.10.246 , ≤ 5.10.* (semver)
Unaffected: 5.15.196 , ≤ 5.15.* (semver)
Unaffected: 6.1.158 , ≤ 6.1.* (semver)
Unaffected: 6.6.115 , ≤ 6.6.* (semver)
Unaffected: 6.12.56 , ≤ 6.12.* (semver)
Unaffected: 6.17.6 , ≤ 6.17.* (semver)
Unaffected: 6.18 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2025-40240\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-06-16T19:41:12.884839Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-06-16T19:41:19.307Z\"}}], \"cna\": {\"title\": \"sctp: avoid NULL dereference when chunk data buffer is missing\", \"metrics\": [{\"cvssV3_1\": {\"version\": \"3.1\", \"baseScore\": 7.5, \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"AV:N - The bug is in the SCTP packet input path (`sctp_rcv` \\u2192 `sctp_inq_push` \\u2192 `sctp_assoc_bh_rcv` \\u2192 `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)-\u003efrag_list` on a shared/cloned GSO skb, and the attacker controls both sides \\u2014 generating the large GSO SCTP packets and the concurrent clone/consumer that mutates the shared shinfo \\u2014 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 \\u2014 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\u0027s 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-\u003edev`) that immediately oopses; no attacker-controlled memory is read back or returned to userspace.\\nI:N - Nothing is written \\u2014 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\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"90017accff61ae89283ad9a51f9ac46ca01633fb\", \"lessThan\": \"61cda2777b07d27459f5cac5a047c3edf9c8a1a9\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"90017accff61ae89283ad9a51f9ac46ca01633fb\", \"lessThan\": \"08165c296597075763130919f2aae59b5822f016\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"90017accff61ae89283ad9a51f9ac46ca01633fb\", \"lessThan\": \"03e80a4b04ef1fb2c61dd63216ab8d3a5dcb196f\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"90017accff61ae89283ad9a51f9ac46ca01633fb\", \"lessThan\": \"4f6da435fb5d8a21cbf8cae5ca5a2ba0e1012b71\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"90017accff61ae89283ad9a51f9ac46ca01633fb\", \"lessThan\": \"cb9055ba30306ede4ad920002233d0659982f1cb\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"90017accff61ae89283ad9a51f9ac46ca01633fb\", \"lessThan\": \"7a832b0f99be19df608cb75c023f8027b1789bd1\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"90017accff61ae89283ad9a51f9ac46ca01633fb\", \"lessThan\": \"89b465b54227c245ddc7cc9ed822231af21123ef\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"90017accff61ae89283ad9a51f9ac46ca01633fb\", \"lessThan\": \"441f0647f7673e0e64d4910ef61a5fb8f16bfb82\", \"versionType\": \"git\"}], \"programFiles\": [\"net/sctp/inqueue.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"4.8\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"4.8\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"5.4.301\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.4.*\"}, {\"status\": \"unaffected\", \"version\": \"5.10.246\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.10.*\"}, {\"status\": \"unaffected\", \"version\": \"5.15.196\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.15.*\"}, {\"status\": \"unaffected\", \"version\": \"6.1.158\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.1.*\"}, {\"status\": \"unaffected\", \"version\": \"6.6.115\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.6.*\"}, {\"status\": \"unaffected\", \"version\": \"6.12.56\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.12.*\"}, {\"status\": \"unaffected\", \"version\": \"6.17.6\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.17.*\"}, {\"status\": \"unaffected\", \"version\": \"6.18\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"net/sctp/inqueue.c\"], \"defaultStatus\": \"affected\"}], \"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\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"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-\u003eskb pointer is dereferenced in the if-block where it\u0027s supposed\\nto be NULL only.\\n\\nchunk-\u003eskb can only be NULL if chunk-\u003ehead_skb is not. Check for frag_list\\ninstead and do it just before replacing chunk-\u003eskb. We\u0027re sure that\\notherwise chunk-\u003eskb is non-NULL because of outer if() condition.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.4.301\", \"versionStartIncluding\": \"4.8\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.10.246\", \"versionStartIncluding\": \"4.8\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.15.196\", \"versionStartIncluding\": \"4.8\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.1.158\", \"versionStartIncluding\": \"4.8\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.6.115\", \"versionStartIncluding\": \"4.8\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.12.56\", \"versionStartIncluding\": \"4.8\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.17.6\", \"versionStartIncluding\": \"4.8\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.18\", \"versionStartIncluding\": \"4.8\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2026-08-05T12:08:44.117Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2025-40240\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-05T12:08:44.117Z\", \"dateReserved\": \"2025-04-16T07:20:57.181Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2025-12-04T15:31:29.715Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.