{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-31446", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-31446", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-04-22T13:53:42.751Z", "updatedAt": "2026-10-19T18:35:48.381Z", "importedAt": "2026-10-24T01:58:02.025Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "ext4: fix use-after-free in update_super_work when racing with umount", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix use-after-free in update_super_work when racing with umount\n\nCommit b98535d09179 (\"ext4: fix bug_on in start_this_handle during umount\nfilesystem\") moved ext4_unregister_sysfs() before flushing s_sb_upd_work\nto prevent new error work from being queued via /proc/fs/ext4/xx/mb_groups\nreads during unmount. However, this introduced a use-after-free because\nupdate_super_work calls ext4_notify_error_sysfs() -> sysfs_notify() which\naccesses the kobject's kernfs_node after it has been freed by kobject_del()\nin ext4_unregister_sysfs():\n\n update_super_work ext4_put_super\n ----------------- --------------\n ext4_unregister_sysfs(sb)\n kobject_del(&sbi->s_kobj)\n __kobject_del()\n sysfs_remove_dir()\n kobj->sd = NULL\n sysfs_put(sd)\n kernfs_put() // RCU free\n ext4_notify_error_sysfs(sbi)\n sysfs_notify(&sbi->s_kobj)\n kn = kobj->sd // stale pointer\n kernfs_get(kn) // UAF on freed kernfs_node\n ext4_journal_destroy()\n flush_work(&sbi->s_sb_upd_work)\n\nInstead of reordering the teardown sequence, fix this by making\next4_notify_error_sysfs() detect that sysfs has already been torn down\nby checking s_kobj.state_in_sysfs, and skipping the sysfs_notify() call\nin that case. A dedicated mutex (s_error_notify_mutex) serializes\next4_notify_error_sysfs() against kobject_del() in ext4_unregister_sysfs()\nto prevent TOCTOU races where the kobject could be deleted between the\nstate_in_sysfs check and the sysfs_notify() call.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "52c3a04f9ec2a16a4204d6274db338cb8d5b2d74", "status": "affected", "versionType": "git", "lessThan": "c8fe17a1b308c3d8c703ebfb049b325f844342c3" }, { "version": "b98535d091795a79336f520b0708457aacf55c67", "status": "affected", "versionType": "git", "lessThan": "c4d829737329f2290dd41e290b7d75effdb2a7ff" }, { "version": "b98535d091795a79336f520b0708457aacf55c67", "status": "affected", "versionType": "git", "lessThan": "9449f99ba04f5dd1c8423ad8a90b3651d7240d1d" }, { "version": "b98535d091795a79336f520b0708457aacf55c67", "status": "affected", "versionType": "git", "lessThan": "034053378dd81837fd6c7a43b37ee2e58d4f0b4e" }, { "version": "b98535d091795a79336f520b0708457aacf55c67", "status": "affected", "versionType": "git", "lessThan": "c97e282f7bfd0c3554c63d289964a5ca6a1d2ffe" }, { "version": "b98535d091795a79336f520b0708457aacf55c67", "status": "affected", "versionType": "git", "lessThan": "08b10e6f37fc533a759e9833af0692242e8b3f93" }, { "version": "b98535d091795a79336f520b0708457aacf55c67", "status": "affected", "versionType": "git", "lessThan": "d15e4b0a418537aafa56b2cb80d44add83e83697" }, { "version": "585ef03c9e79672781f954daae730dfe24bf3a46", "status": "affected", "versionType": "git" }, { "version": "afe490e48d47df1b3f64012835c1bc2f075a8c8b", "status": "affected", "versionType": "git" }, { "version": "5.15.38", "status": "affected", "versionType": "semver", "lessThan": "5.15.203" }, { "version": "5.10.114", "status": "affected", "versionType": "semver", "lessThan": "5.11" }, { "version": "5.17.6", "status": "affected", "versionType": "semver", "lessThan": "5.18" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "5.18", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "5.18" }, { "version": "5.15.203", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.168", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.131", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.80", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.21", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "6.19.11", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.19.*" }, { "version": "7.0", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }