{"id":"DEBIAN-CVE-2026-31555","details":"In the Linux kernel, the following vulnerability has been resolved:  futex: Clear stale exiting pointer in futex_lock_pi() retry path  Fuzzying/stressing futexes triggered:      WARNING: kernel/futex/core.c:825 at wait_for_owner_exiting+0x7a/0x80, CPU#11: futex_lock_pi_s/524  When futex_lock_pi_atomic() sees the owner is exiting, it returns -EBUSY and stores a refcounted task pointer in 'exiting'.  After wait_for_owner_exiting() consumes that reference, the local pointer is never reset to nil. Upon a retry, if futex_lock_pi_atomic() returns a different error, the bogus pointer is passed to wait_for_owner_exiting().    CPU0\t\t\t     CPU1\t\t       CPU2   futex_lock_pi(uaddr)   // acquires the PI futex   exit()     futex_cleanup_begin()       futex_state = EXITING; \t\t\t     futex_lock_pi(uaddr) \t\t\t       futex_lock_pi_atomic() \t\t\t\t attach_to_pi_owner() \t\t\t\t   // observes EXITING \t\t\t\t   *exiting = owner;  // takes ref \t\t\t\t   return -EBUSY \t\t\t       wait_for_owner_exiting(-EBUSY, owner) \t\t\t\t put_task_struct();   // drops ref \t\t\t       // exiting still points to owner \t\t\t       goto retry; \t\t\t       futex_lock_pi_atomic() \t\t\t\t lock_pi_update_atomic() \t\t\t\t   cmpxchg(uaddr) \t\t\t\t\t*uaddr ^= WAITERS // whatever \t\t\t\t   // value changed \t\t\t\t return -EAGAIN; \t\t\t       wait_for_owner_exiting(-EAGAIN, exiting) // stale \t\t\t\t WARN_ON_ONCE(exiting)  Fix this by resetting upon retry, essentially aligning it with requeue_pi.","modified":"2026-09-14T17:03:04.628092350Z","published":"2026-04-24T15:16:29.837Z","upstream":["CVE-2026-31555"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-31555"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.170-1"}]}],"versions":["6.1.106-1","6.1.106-2","6.1.106-3","6.1.112-1","6.1.115-1","6.1.119-1","6.1.123-1","6.1.124-1","6.1.128-1","6.1.129-1","6.1.133-1","6.1.135-1","6.1.137-1","6.1.139-1","6.1.140-1","6.1.147-1","6.1.148-1","6.1.153-1","6.1.158-1","6.1.159-1","6.1.162-1","6.1.164-1","6.1.27-1","6.1.37-1","6.1.38-1","6.1.38-2","6.1.38-2~bpo11+1","6.1.38-3","6.1.38-4","6.1.38-4~bpo11+1","6.1.52-1","6.1.55-1","6.1.55-1~bpo11+1","6.1.64-1","6.1.66-1","6.1.67-1","6.1.69-1","6.1.69-1~bpo11+1","6.1.76-1","6.1.76-1~bpo11+1","6.1.82-1","6.1.85-1","6.1.90-1","6.1.90-1~bpo11+1","6.1.94-1","6.1.94-1~bpo11+1","6.1.98-1","6.1.99-1"],"ecosystem_specific":{"urgency":"not 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