Bug 2516354 (CVE-2026-72383)

Summary: CVE-2026-72383 kernel: sctp: fix addr_wq_timer race in sctp_free_addr_wq()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Stream Control Transmission Protocol (SCTP) implementation. A race condition exists in the `sctp_free_addr_wq()` function during the cleanup of network address work queues. This allows a timer handler to access memory that has already been freed, leading to a use-after-free vulnerability. Such a vulnerability can cause system instability, including crashes, and potentially lead to denial of service.
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Description OSIDB Bzimport 2026-08-15 06:08:07 UTC 
In the Linux kernel, the following vulnerability has been resolved:

sctp: fix addr_wq_timer race in sctp_free_addr_wq()

sctp_free_addr_wq() previously removed addr_wq_timer using timer_delete()
while holding addr_wq_lock. However, timer_delete() does not guarantee that
a currently running timer handler has completed.

This allows a race with sctp_addr_wq_timeout_handler(), where the handler
may still run after addr_waitq has been freed, acquire addr_wq_lock, and
access freed memory, leading to a use-after-free.

Fix this by calling timer_shutdown_sync() before taking addr_wq_lock.  This
guarantees that any in-flight timer handler has finished and prevents the
timer from being re-armed during teardown, making subsequent cleanup safe.
Comment 1 Keith Grant 2026-08-19 14:47:27 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081518-CVE-2026-72383-bf62@gregkh/T