ACK: [SRU][Q][PATCH 0/1] CVE-2026-53260

[Tim Whisonant]

On Fri, Jul 17, 2026 at 06:24:35PM +0300, Cengiz Can via kernel-team wrote:
> https://ubuntu.com/security/CVE-2026-53260
> 
> [ Impact ]
> 
> A race condition exists in reqsk_queue_hash_req() in the TCP stack. On
> PREEMPT_RT kernels, the function can be preempted between mod_timer() and
> refcount_set(), allowing the request socket timer to fire and abort the reqsk
> before its refcounts are initialized. This leads to a refcount underflow and
> use-after-free of the request socket, which an attacker could exploit to
> compromise the system (CVSS 9.8).
> 
> [ Fix ]
> 
> questing: backported with AI-assisted adaptation
> 
> [ Test Plan ]
> 
> Boot tested.
> 
> [ Where Problems Could Occur ]
> 
> A mistake in this fix could disrupt TCP request socket handling in the inet
> connection sock subsystem, potentially causing incorrect timer or refcount
> behavior during connection establishment, which may result in dropped
> connections or socket leaks.
> 

Acked-by: Tim Whisonant <tim.whisonant at canonical.com>