{"id":"CVE-2026-53197","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-53197","generatedAt":"2026-10-28T09:27:01.404Z","title":"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…","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.","published":"2026-06-25T09:16:37.000Z","lastModified":"2026-07-06T12:33:30.000Z","status":"Analyzed","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-667"],"affected":["linux/linux kernel"],"epss":{"score":0.00124,"percentile":0.02088,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.12%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/822b98d354e63e8249e85473c5f3c519f3c9cecc","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a13ca53e47e500854a3b9ec18b5dc83acfec863e","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c8a8a75b733467b00c08b91a38dbaf207a08ed6e","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-53197","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}