Bug 2502358 (CVE-2026-63911) - CVE-2026-63911 kernel: xfrm: iptfs: reset runtime state when cloning SAs
Summary: CVE-2026-63911 kernel: xfrm: iptfs: reset runtime state when cloning SAs
Keywords:
Status: NEW
Alias: CVE-2026-63911
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-19 16:03 UTC by OSIDB Bzimport
Modified: 2026-07-21 21:01 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2026-07-19 16:03:49 UTC
In the Linux kernel, the following vulnerability has been resolved:

xfrm: iptfs: reset runtime state when cloning SAs

iptfs_clone_state() clones the IPTFS mode data with kmemdup(). This
copies runtime objects which must not be shared with the original SA,
including the embedded sk_buff_head, hrtimers, spinlock, and in-flight
reassembly/reorder state.

If xfrm_state_migrate() fails after clone_state() but before the later
init_state() call has reinitialized those fields, the cloned state can be
destroyed by xfrm_state_gc_task() with list and timer state copied from the
original SA. With queued packets this lets the clone splice and free skbs
owned by the original IPTFS queue, leading to use-after-free and
double-free reports in iptfs_destroy_state() and skb release paths.

Reinitialize the clone's runtime state before publishing it through
x->mode_data. Because clone_state() now publishes a destroyable mode_data
object before init_state(), take the mode callback module reference there.
Avoid taking it again from __iptfs_init_state() for the same object.


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