{"cve":"CVE-2026-80660","nvd":{"published":"2026-08-28T08:16:51.160","modified":"2026-08-28T08:16:51.160","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nhwmon: (occ) unregister sysfs devices outside occ lock\n\nocc_active(false) and occ_shutdown() unregister sysfs-backed devices while\nocc->lock is held.  hwmon_device_unregister() and sysfs_remove_group() can\nwait for active sysfs callbacks to drain, and those callbacks can enter the\nOCC update path and try to take occ->lock again.  That gives the unregister\npaths the lock ordering occ->lock -> sysfs callback drain, while a callback\nhas the opposite edge sysfs callback -> occ->lock.\n\nThis issue was found by our static analysis tool and then manually\nreviewed against the current tree.\n\nThe grounded PoC kept the real unregister and callback carrier:\n\n  occ_shutdown()\n  hwmon_device_unregister()\n  occ_show_temp_1()\n  occ_update_response()\n\nLockdep reported the circular dependency with occ_shutdown() already\nholding the OCC mutex and hwmon_device_unregister() waiting on the sysfs\nside:\n\n  WARNING: possible circular locking dependency detected\n  ... (sysfs_lock) ... at: hwmon_device_unregister+0x12/0x30 [vuln_msv]\n  ... (&test_occ.lock) ... at: occ_shutdown.constprop.0+0xe/0x40 [vuln_msv]\n  occ_update_response.isra.0+0xb/0x20 [vuln_msv]\n  occ_show_temp_1.constprop.0.isra.0+0x23/0x40 [vuln_msv]\n  *** DEADLOCK ***\n\nSerialize hwmon registration and removal with a separate hwmon_lock.\nUnder that lock, detach occ->hwmon and update occ->active while occ->lock\nis held so concurrent OCC state changes still see a stable state, then\ndrop occ->lock before calling hwmon_device_unregister().  Remove the\ndriver sysfs group before taking occ->lock in occ_shutdown(), so draining\nthe driver attributes cannot wait while the OCC mutex is held.  Also make\nOCC update callbacks return -ENODEV after deactivation, so callbacks that\nalready passed sysfs active protection do not poll the hardware after\nteardown has detached the hwmon device.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/2092952f22a7da98e76e84139ae202b1fc7ba899","https://git.kernel.org/stable/c/2a4c80ff3571498ec6a916273304b6650026b1b0","https://git.kernel.org/stable/c/7ee43ec8e6774774abbe9dc3027225e01bc964a5","https://git.kernel.org/stable/c/e31408734332b8cc611342cdaaab6ba492180156","https://git.kernel.org/stable/c/e7fd81e9fb1fe476d2131fec66c1138457810ed4"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:50:50.842544443+00:00"},"epss":{"cve":"CVE-2026-80660","score":0.00215,"percentile":0.11871,"date":"2026-11-01"},"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."]}