Improper Locking Affecting linux-qemu-melange package, versions <6.18.38-r0
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-CHAINGUARDLATEST-LINUXQEMUMELANGE-17949833
- published11 Jul 2026
- disclosed25 Jun 2026
Introduced: 25 Jun 2026
CVE-2026-53197 (opens in a new tab)How to fix?
Upgrade Chainguard linux-qemu-melange to version 6.18.38-r0 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream linux-qemu-melange package and not the linux-qemu-melange package as distributed by Chainguard.
See How to fix? for Chainguard relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
xfrm: iptfs: fix ABBA deadlock in iptfs_destroy_state()
iptfs_destroy_state() calls hrtimer_cancel() while holding a spinlock that the timer callback also acquires, leading to an ABBA deadlock on SMP systems.
For the output timer (iptfs_timer):
- iptfs_destroy_state() holds x->lock, calls hrtimer_cancel()
- iptfs_delay_timer() callback takes x->lock
For the drop timer (drop_timer):
- iptfs_destroy_state() holds drop_lock, calls hrtimer_cancel()
- iptfs_drop_timer() callback takes drop_lock
Both timers use HRTIMER_MODE_REL_SOFT, so their callbacks run in softirq context. When hrtimer_cancel() is called for a soft timer that is currently executing on another CPU, hrtimer_cancel_wait_running() spins on softirq_expiry_lock -- the same lock held by the softirq running the callback. If the callback is blocked waiting for the spinlock held by the caller of hrtimer_cancel(), a circular dependency forms:
CPU 0: holds lock_A -> waits for softirq_expiry_lock CPU 1: holds softirq_expiry_lock -> waits for lock_A
Fix by calling hrtimer_cancel() before acquiring the respective locks. hrtimer_cancel() is safe to call without holding any lock and will wait for any in-progress callback to complete. For the output timer, the lock is still acquired afterwards to drain the packet queue. For the drop timer, the lock/unlock pair is removed entirely since it only existed to serialize with the timer callback, which hrtimer_cancel() already guarantees.
Found by source code audit.