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CVE-2026-46227

sctp: revalidate list cursor after sctp_sendmsg_to_asoc() in SCTP_SENDALL

At a glance

Severity
HIGH 7.8
EPSS
EPSS 0.10 % · percentile 1 (2026-10-27)
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Modified

Description

In the Linux kernel, the following vulnerability has been resolved: sctp: revalidate list cursor after sctp_sendmsg_to_asoc() in SCTP_SENDALL The SCTP_SENDALL path in sctp_sendmsg() iterates ep->asocs with list_for_each_entry_safe(), which caches the next entry in @tmp before the loop body runs. The body calls sctp_sendmsg_to_asoc(), which may drop the socket lock inside sctp_wait_for_sndbuf(). While the lock is dropped, another thread can SCTP_SOCKOPT_PEELOFF the association cached in @tmp, migrating it to a new endpoint via sctp_sock_migrate() (list_del_init() + list_add_tail() to newep->asocs), and optionally close the new socket which frees the association via kfree_rcu(). The cached @tmp can also be freed by a network ABORT for that association, processed in softirq while the lock is dropped. sctp_wait_for_sndbuf() revalidates @asoc (the current entry) on re-lock via the "sk != asoc->base.sk" and "asoc->base.dead" checks, but nothing revalidates @tmp. After a successful return, the iterator advances to the stale @tmp, yielding either a use-after-free (if the peeled socket was closed) or a list-walk onto the new endpoint's list head (type confusion of &newep->asocs as a struct sctp_association *). Both are reachable from CapEff=0; the type-confusion path gives controlled indirect call via the outqueue.sched->init_sid pointer. Fix by re-deriving @tmp from @asoc after sctp_sendmsg_to_asoc() returns. @asoc is known to still be on ep->asocs at that point: the only callers that list_del an association from ep->asocs are sctp_association_free() (which sets asoc->base.dead) and sctp_assoc_migrate() (which changes asoc->base.sk), and sctp_wait_for_sndbuf() checks both under the lock before any successful return; a tripped check propagates as err < 0 and the loop bails before the re-derive. The SCTP_ABORT path in sctp_sendmsg_check_sflags() returns 0 and the loop hits 'continue' before sctp_sendmsg_to_asoc() is ever called, so the @tmp cached by list_for_each_entry_safe() still covers the lock-held free that ba59fb027307 ("sctp: walk the list of asoc safely") was added for.

Scores

VersionScoreVectorScored by
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HLinux
CVSS 3.1HIGH 7.0CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:Hredhat-SADP
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)
CVSS 3.1HIGH 7.0CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary)

Weaknesses (CWE)

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
Linux · Linuxaffected 4910280503f3af2857d5aa77e35b22d93a8960a8 < f3a3f0b406b4b7eb3cea35a23fa2bf170848b104 ; affected 4910280503f3af2857d5aa77e35b22d93a8960a8 < 0dbc8cde64280fc37cdd678cced34eaf96cfb197 ; affected 4910280503f3af2857d5aa77e35b22d93a8960a8 < 0c7b55974f97b78d1109025eadf084e74cbf330f ; affected 4910280503f3af2857d5aa77e35b22d93a8960a8 < 1bfb06ecb00f7fdf35dba8e8f2877346cbe5e078 ; affected 4910280503f3af2857d5aa77e35b22d93a8960a8 < 6187a172d6ed57d6b2c327836e4407c6456e639d ; affected 4910280503f3af2857d5aa77e35b22d93a8960a8 < c9dadb31f36045a8cb65df4bd75e7237ef21a4b5
Linux · Linuxaffected 4.17 ; unaffected 0 < 4.17 ; unaffected 5.10.258 ≤ 5.10.* ; unaffected 5.15.209 ≤ 5.15.* ; unaffected 6.1.175 ≤ 6.1.* ; unaffected 6.6.140 ≤ 6.6.*

References

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD