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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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    "redhat_vex": {
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      "product_status:fixed": "2366",
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      "title": "SUSE CVE CVE-2025-40240",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2025-40240.json",
      "version": "47"
    },
    "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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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.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.