{"id":"CVE-2026-80920","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring: defer eventfd signaling when queued from a wakeup handler\n\nio_req_local_work_add() signals the CQ ring eventfd inline when it is the\none to push the first ent…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring: defer eventfd signaling when queued from a wakeup handler\n\nio_req_local_work_add() signals the CQ ring eventfd inline when it is the\none to push the first ent…","severity":"medium","vendor":"Linux","product":"Linux","affected":["Linux >= 21a091b970cdbcf3e8ff829234b51be6f9192766 < e22f4494cc9487d326e5e3067f33dea7c1e442b2","Linux >= 21a091b970cdbcf3e8ff829234b51be6f9192766 < b6bb334b0e9348887e3e55e1f494b0c3b8fbf59f","Linux >= 21a091b970cdbcf3e8ff829234b51be6f9192766 < 40b6ccf68731809ceb85c6e9f0f8f2ed61c7aa5a","Linux >= 21a091b970cdbcf3e8ff829234b51be6f9192766 < cd305ee3633a45fcf5f3a5d83f99f3cb77d87b6e","Linux 6.1"],"published":"2026-09-09","updated":"2026-09-09","sourceUpdated":"2026-09-09T17:17:47.120","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-80920","references":[{"url":"https://git.kernel.org/stable/c/40b6ccf68731809ceb85c6e9f0f8f2ed61c7aa5a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b6bb334b0e9348887e3e55e1f494b0c3b8fbf59f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/cd305ee3633a45fcf5f3a5d83f99f3cb77d87b6e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e22f4494cc9487d326e5e3067f33dea7c1e442b2","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80920.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-80920"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2531052"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80920"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80920"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80920.mbox"},{"url":"https://git.kernel.org/stable/c/d0c240f25e654442a72af5ca021a02165ccce638"},{"url":"https://git.kernel.org/stable/c/9d984451baf768ecd9e1fdad4637b729fcb2c9d5"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"ingestedAt":"2026-09-09T17:16:03.091Z","epss":0.00167,"epssPercentile":0.0588,"cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"vendor","cwe":["CWE-821"],"slug":"CVE-2026-80920","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nio_uring: defer eventfd signaling when queued from a wakeup handler\n\nio_req_local_work_add() signals the CQ ring eventfd inline when it is the\none to push the first entry onto ->work_list. For DEFER_TASKRUN rings that\nadd is frequently done from a waitqueue wakeup handler, where an\narbitrary waitqueue lock is held.\n\neventfd_signal_mask() only refuses to recurse when current->in_eventfd\nis set, but that bit is set by eventfd_signal_mask() itself. If the wake\nchain starts somewhere else, signal goes out inline and can feed back\ninto epoll.\n\nAdd IOU_F_TWQ_IN_WAKE, set it on the task_work add done from the three\nwaitqueue callbacks, and use it to force io_eventfd_signal() down the\nexisting call_rcu_hurry() deferral instead of signaling inline.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-10-20 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80920.json)","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":225651,"id":"CVE-2026-80920","ts":1792498334919,"field":"cvss","old":null,"new":"5.5"},{"seq":225650,"id":"CVE-2026-80920","ts":1792498334919,"field":"severity","old":"none","new":"medium"}]}