{"apiVersion":"1.0","identifier":"CVE-2026-74628","description":"In the Linux kernel, the following vulnerability has been resolved: net/x25: fix use-after-free of the socket by its timers The x25 timers are armed with mod_timer() and cancelled with timer_delete(), so a pending timer holds no reference on the socket and a cancel does not wait for a callback already running on another CPU. x25_heartbeat_expiry() also rearms unconditionally, so it can reinstall sk->sk_timer after __x25_destroy_socket() has passed its cancel point. The following __sock_put() frees the socket while the timer is still queued, and the next expiry uses freed memory. KASAN reports a slab-use-after-free on the kmalloc-2k object freed by close(). timer_delete_sync() cannot be used here: x25_heartbeat_expiry() and x25_timer_expiry() both reach the cancels from inside the timer they would wait on, through __x25_destroy_socket() and x25_disconnect(). Arm the timers with sk_reset_timer() and cancel them with sk_stop_timer() so that an armed timer owns a reference, and release it in both expiry handlers. Rearm the heartbeat only while sk_hashed(sk) is still true, since __x25_destroy_socket() unlinks the socket before dropping it. Arm the deferred destroy timer the same way and drop its reference in x25_destroy_timer(). Reproduced on net with KASAN, with the heartbeat period shortened so the window recurs. With this patch the reproducer no longer triggers a report and /proc/net/x25 drains. Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>","publishedAt":"2026-08-22T16:16:35","lastModifiedAt":"2026-08-27T13:18:34","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-74628","cvssScore":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","epssProbability":0.005,"riskScore":1.02,"affectedProduct":"Linux kernel","affectedVersions":"unknown","vulnerabilityType":"Kernel","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-74628","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-74628","en":"https://www.redsauce.net/en/cves/CVE-2026-74628","fr":"https://www.redsauce.net/fr/cves/CVE-2026-74628","pt":"https://www.redsauce.net/pt/cves/CVE-2026-74628","de":"https://www.redsauce.net/de/cves/CVE-2026-74628","sk":"https://www.redsauce.net/sk/cves/CVE-2026-74628","el":"https://www.redsauce.net/el/cves/CVE-2026-74628"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-74628"}}