Linux Kernel SCTP SENDALL Use-After-Free via PEEL Migration
CVE-2026-46227 Published on May 28, 2026

sctp: revalidate list cursor after sctp_sendmsg_to_asoc() in SCTP_SENDALL
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.

NVD

Vulnerability Analysis

CVE-2026-46227 can be exploited with local system access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.

Attack Vector:
LOCAL
Attack Complexity:
HIGH
Privileges Required:
LOW
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
HIGH
Availability Impact:
HIGH

Weakness Type

What is a TOCTTOU Vulnerability?

The software checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. This can cause the software to perform invalid actions when the resource is in an unexpected state. This weakness can be security-relevant when an attacker can influence the state of the resource between check and use. This can happen with shared resources such as files, memory, or even variables in multithreaded programs.

CVE-2026-46227 has been classified to as a TOCTTOU vulnerability or weakness.


Products Associated with CVE-2026-46227

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Linux Kernel
 
Red Hat Enterprise Linux Eus
 
Red Hat Rhel E4s
 
Red Hat Rhel Aus
 
Red Hat Rhel Eus Long Life
 
Red Hat Rhel Tus
 
Red Hat Enterprise Linux (RHEL)
 
Red Hat Rhel Eus
 

Affected Versions

Linux: Linux: Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 10.0 Extended Update Support: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support: Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On: Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support: Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On: Red Hat Enterprise Linux 8.8 Telecommunications Update Service: Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.6 Extended Update Support: Red Hat Enterprise Linux 6: Red Hat Enterprise Linux 7:

Exploit Probability

EPSS
0.13%
Percentile
2.56%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.