sctp: clear new_transport when removing a peer

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-74586
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-22 16:16:30 UTC
Updated2026-08-25 06:18:32 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: sctp: clear new_transport when removing a peer sctp_process_asconf_param() stores a newly added peer transport in asoc->new_transport. After all parameters in the ASCONF chunk have been processed, sctp_sf_do_asconf() uses this pointer to send a HEARTBEAT to the new transport. An authenticated ASCONF from a remote SCTP peer can add a transport and remove it again with a wildcard DEL-IP parameter in the same chunk. The wildcard deletion preserves the transport on which the ASCONF arrived, but removes the newly added transport through sctp_assoc_del_nonprimary_peers(). The removal does not clear asoc->new_transport, leaving it pointing to the removed transport. sctp_sf_do_asconf() then creates a HEARTBEAT whose chunk->transport points to the removed transport without holding a transport reference. During local address replacement, src_out_of_asoc_ok keeps this HEARTBEAT on control_chunk_list. After the transport is freed by RCU, a successful ASCONF_ACK for the replacement address releases the queued HEARTBEAT and sctp_outq_select_transport() reads the freed transport's state. The issue was found during a static audit of SCTP objects. With an authenticated peer, the reproducer triggered the same KASAN report in 2 of 2 unpatched runs on a KASAN-enabled netdev/main kernel: BUG: KASAN: slab-use-after-free in sctp_outq_select_transport Read of size 4 at addr ffff88800b9bd95c by task python3/197 Call Trace: sctp_outq_select_transport+0x549/0x8b0 [sctp] sctp_outq_flush+0x306/0x2c60 [sctp] sctp_transport_immediate_rtx+0xaf/0x260 [sctp] sctp_process_asconf_ack+0xa48/0xf70 [sctp] Allocated by task 197: sctp_transport_new+0x68/0x650 [sctp] sctp_assoc_add_peer+0x258/0x12a0 [sctp] sctp_process_asconf+0x5e9/0x1090 [sctp] Last potentially related work creation: __call_rcu_common.constprop.0+0x77/0xb70 sctp_assoc_del_nonprimary_peers+0x7c/0xd0 [sctp] sctp_process_asconf+0xd9c/0x1090 [sctp] The first invalid access was a four-byte read of transport->state at net/sctp/outqueue.c:833. The same reproducer completed the full authenticated ASCONF and local-address replacement sequence with this change without a KASAN report or oops. Clear new_transport when its peer is removed, before it can be used to create the HEARTBEAT.

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 0.405440000 (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 6af29ccc223b0feb6fc6112281c3fa3cdb1afddf c0f973bb5118dd1b146cda3fcc8af6f6057befec git Not specified
CNA Linux Linux affected 6af29ccc223b0feb6fc6112281c3fa3cdb1afddf 3b539b317cd052236fed0350364ff1268996ba46 git Not specified
CNA Linux Linux affected 6af29ccc223b0feb6fc6112281c3fa3cdb1afddf db9d8e3b670f841755bc2018f178472dc6064d27 git Not specified
CNA Linux Linux affected 6af29ccc223b0feb6fc6112281c3fa3cdb1afddf 31efa656cf6aface26e88f038c14f22ee6ca1500 git Not specified
CNA Linux Linux affected 6af29ccc223b0feb6fc6112281c3fa3cdb1afddf 291accf36febce751021888de5f15090f4875b56 git Not specified
CNA Linux Linux affected 6af29ccc223b0feb6fc6112281c3fa3cdb1afddf ca33df36aa0143a1d04f57d2086020c12e7eddb7 git Not specified
CNA Linux Linux affected 6af29ccc223b0feb6fc6112281c3fa3cdb1afddf 163847552a571bd55094291f4ffcdc1de0f14a7b git Not specified
CNA Linux Linux affected 6af29ccc223b0feb6fc6112281c3fa3cdb1afddf beb33f8ee1ca83acddb2a5ae80f3d22ec550b4c3 git Not specified
CNA Linux Linux affected 3.2 Not specified
CNA Linux Linux unaffected 3.2 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/beb33f8ee1ca83acddb2a5ae80f3d22ec550b4c3 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/3b539b317cd052236fed0350364ff1268996ba46 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/31efa656cf6aface26e88f038c14f22ee6ca1500 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/163847552a571bd55094291f4ffcdc1de0f14a7b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c0f973bb5118dd1b146cda3fcc8af6f6057befec 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/db9d8e3b670f841755bc2018f178472dc6064d27 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/291accf36febce751021888de5f15090f4875b56 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ca33df36aa0143a1d04f57d2086020c12e7eddb7 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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