sctp: fix use-after-free of cached ASCONF chunk

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-74587
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-22 16:16:30 UTC
Updated2026-08-25 06:18:33 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: sctp: fix use-after-free of cached ASCONF chunk addip_last_asconf caches the outstanding outbound ASCONF chunk. The normal ASCONF-ACK completion path releases the chunk and clears the pointer. However, sctp_asconf_queue_teardown() releases the cached chunk without clearing addip_last_asconf. During peer restart handling, sctp_sf_do_dupcook_a() queues SCTP_CMD_PURGE_ASCONF_QUEUE, which invokes sctp_asconf_queue_teardown() while the association remains alive and leaves the pointer dangling. A delayed authenticated ASCONF-ACK can then reach sctp_sf_do_asconf_ack(), which accesses the stale chunk and passes it to sctp_process_asconf_ack(), causing a use-after-free and a second release. Clearing the pointer exposes a race with T4 expiry. Peer restart handling queues the timer stop before the purge, but SCTP_CMD_TIMER_STOP uses timer_delete(), which does not wait for a callback already running on another CPU. Such a callback can reach sctp_sf_t4_timer_expire() after the purge and dereference NULL. Clear addip_last_asconf after releasing the cached chunk, and make sctp_sf_t4_timer_expire() consume a stale T4 expiry if no outstanding ASCONF remains.

Risk And Classification

Primary CVSS: v3.1 9.8 CRITICAL from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.005000000 probability, percentile 0.405450000 (date 2026-08-25)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected a000c01e60e40e15304ffe48fff051d17a7bea91 10459b03e2d9ee12435e96f587de4d4cacdbf435 git Not specified
CNA Linux Linux affected a000c01e60e40e15304ffe48fff051d17a7bea91 e1bb114e09372fd6e03387ced9ef566da336ed6c git Not specified
CNA Linux Linux affected a000c01e60e40e15304ffe48fff051d17a7bea91 179676f0166230c80053a392303485b37c93dd33 git Not specified
CNA Linux Linux affected a000c01e60e40e15304ffe48fff051d17a7bea91 dc67d528c2fa939cec7fe3bf7f3089c8d281ca3d git Not specified
CNA Linux Linux affected a000c01e60e40e15304ffe48fff051d17a7bea91 618b5c6d049896fcfabb91afc072954c92cb2693 git Not specified
CNA Linux Linux affected a000c01e60e40e15304ffe48fff051d17a7bea91 07daf4f9750104960a1d60831b2353c0d41f35fb git Not specified
CNA Linux Linux affected a000c01e60e40e15304ffe48fff051d17a7bea91 d949992bc3f00027a2c755e860a11950c75f6073 git Not specified
CNA Linux Linux affected a000c01e60e40e15304ffe48fff051d17a7bea91 8c283e7b56adce00193837f3311b06662466fb21 git Not specified
CNA Linux Linux affected 3.0 Not specified
CNA Linux Linux unaffected 3.0 semver Not specified
CNA Linux Linux unaffected 5.10.265 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.216 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.183 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.152 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.104 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.45 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.9 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/e1bb114e09372fd6e03387ced9ef566da336ed6c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/dc67d528c2fa939cec7fe3bf7f3089c8d281ca3d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/07daf4f9750104960a1d60831b2353c0d41f35fb 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/618b5c6d049896fcfabb91afc072954c92cb2693 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/8c283e7b56adce00193837f3311b06662466fb21 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/179676f0166230c80053a392303485b37c93dd33 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/10459b03e2d9ee12435e96f587de4d4cacdbf435 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/d949992bc3f00027a2c755e860a11950c75f6073 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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