{"cve":"CVE-2026-53197","nvd":{"published":"2026-06-25T09:16:37.227","modified":"2026-07-06T12:33:29.513","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: iptfs: fix ABBA deadlock in iptfs_destroy_state()\n\niptfs_destroy_state() calls hrtimer_cancel() while holding a spinlock\nthat the timer callback also acquires, leading to an ABBA deadlock on\nSMP systems.\n\nFor the output timer (iptfs_timer):\n  - iptfs_destroy_state() holds x->lock, calls hrtimer_cancel()\n  - iptfs_delay_timer() callback takes x->lock\n\nFor the drop timer (drop_timer):\n  - iptfs_destroy_state() holds drop_lock, calls hrtimer_cancel()\n  - iptfs_drop_timer() callback takes drop_lock\n\nBoth timers use HRTIMER_MODE_REL_SOFT, so their callbacks run in softirq\ncontext.  When hrtimer_cancel() is called for a soft timer that is\ncurrently executing on another CPU, hrtimer_cancel_wait_running() spins\non softirq_expiry_lock -- the same lock held by the softirq running the\ncallback.  If the callback is blocked waiting for the spinlock held by\nthe caller of hrtimer_cancel(), a circular dependency forms:\n\n  CPU 0: holds lock_A -> waits for softirq_expiry_lock\n  CPU 1: holds softirq_expiry_lock -> waits for lock_A\n\nFix by calling hrtimer_cancel() before acquiring the respective locks.\nhrtimer_cancel() is safe to call without holding any lock and will wait\nfor any in-progress callback to complete.  For the output timer, the\nlock is still acquired afterwards to drain the packet queue.  For the\ndrop timer, the lock/unlock pair is removed entirely since it only\nexisted to serialize with the timer callback, which hrtimer_cancel()\nalready guarantees.\n\nFound by source code audit.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-667"],"references":["https://git.kernel.org/stable/c/822b98d354e63e8249e85473c5f3c519f3c9cecc","https://git.kernel.org/stable/c/a13ca53e47e500854a3b9ec18b5dc83acfec863e","https://git.kernel.org/stable/c/c8a8a75b733467b00c08b91a38dbaf207a08ed6e"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:41:17.107060303+00:00"},"epss":{"cve":"CVE-2026-53197","score":0.00124,"percentile":0.02083,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}