{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-72071", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.904Z", "datePublished": "2026-08-15T05:52:23.215Z", "dateUpdated": "2026-08-15T05:52:23.215Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-15T05:52:23.215Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing/user_events: Fix use-after-free in user_event_mm_dup()\n\nuser_event_mm_dup() walks the parent mm's enabler list locklessly under\nrcu_read_lock() during fork() (from copy_process()); it does not take\nevent_mutex:\n\n\trcu_read_lock();\n\tlist_for_each_entry_rcu(enabler, &old_mm->enablers, mm_enablers_link)\n\t\tenabler->event = user_event_get(orig->event);\n\nuser_event_enabler_destroy() removes an enabler from that list with\nlist_del_rcu() and then, without waiting for a grace period, drops the\nenabler's user_event reference with user_event_put() and frees the enabler\nwith kfree(). A reader that loaded the enabler before the list_del_rcu()\ncan still be walking it, which leads to two use-after-frees:\n\n - kfree(enabler) frees the enabler while that reader dereferences\n enabler->event.\n\n - user_event_put() may drop the last reference to the user_event, which\n is then freed (via delayed_destroy_user_event() on a work queue), while\n the same reader does user_event_get(orig->event) on it.\n\nBoth are reachable by an unprivileged task that can open user_events_data:\none multithreaded process that registers an enabler and then concurrently\nunregisters it and calls fork() triggers the race. KASAN reports a\nslab-use-after-free in user_event_mm_dup() during clone(), with a\n\"refcount_t: addition on 0\" warning when the user_event is freed.\n\nThe enabler use-after-free was found first; the user_event one was reported\nby XIAO WU, and the earlier enabler-only fix did not address it.\n\nDefer both the user_event_put() and the kfree(enabler) to a work item\nqueued with queue_rcu_work(), so they run only after an RCU grace period,\nonce all readers walking the enabler list have finished. The put must run\nin process context because user_event_put() takes event_mutex on the last\nreference, so a work queue is used rather than call_rcu(). The now-unlocked\nput lets the locked argument of user_event_enabler_destroy() be removed;\nall callers are updated." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/trace/trace_events_user.c" ], "versions": [ { "version": "7235759084a4f8524a46bd2638885ff3b34ce279", "lessThan": "25acb6711da6fa0382744fa92bd6d42a22c1ae68", "status": "affected", "versionType": "git" }, { "version": "7235759084a4f8524a46bd2638885ff3b34ce279", "lessThan": "95400e7039cdfeb0b53652d521d766f1698cae95", "status": "affected", "versionType": "git" }, { "version": "7235759084a4f8524a46bd2638885ff3b34ce279", "lessThan": "b33ac2d39953efb12f598c0dae242c5f644ea669", "status": "affected", "versionType": "git" }, { "version": "7235759084a4f8524a46bd2638885ff3b34ce279", "lessThan": "05b24f68f78ff3a1ef7f015f7327b35886b741f6", "status": "affected", "versionType": "git" }, { "version": "7235759084a4f8524a46bd2638885ff3b34ce279", "lessThan": "50fd6dd755c6e48a38af2fa4621167eea56829c2", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/trace/trace_events_user.c" ], "versions": [ { "version": "6.4", "status": "affected" }, { "version": "0", "lessThan": "6.4", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.148", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2-rc3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.4", "versionEndExcluding": "6.6.148" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.4", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.4", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.4", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.4", "versionEndExcluding": "7.2-rc3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/25acb6711da6fa0382744fa92bd6d42a22c1ae68" }, { "url": "https://git.kernel.org/stable/c/95400e7039cdfeb0b53652d521d766f1698cae95" }, { "url": "https://git.kernel.org/stable/c/b33ac2d39953efb12f598c0dae242c5f644ea669" }, { "url": "https://git.kernel.org/stable/c/05b24f68f78ff3a1ef7f015f7327b35886b741f6" }, { "url": "https://git.kernel.org/stable/c/50fd6dd755c6e48a38af2fa4621167eea56829c2" } ], "title": "tracing/user_events: Fix use-after-free in user_event_mm_dup()", "x_generator": { "engine": "bippy-1.2.0" } } } }