{"id":"CVE-2026-89732","title":"kernel: usb: gadget: f_fs: Prevent deadlock during ep0 read loop (CVE-2026-89732)","summary":"A flaw was found in the Linux kernel's USB FunctionFS (f_fs) module. A local attacker could exploit a deadlock vulnerability in the ffs_ep0_read() function. This occurs when a userspace daemon polls ep0 and the USB gadget is simultaneously…","severity":"medium","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-833","vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","affected":["openshift_container_platform 4"],"published":"2026-09-11","updated":"2026-09-21","sourceUpdated":"2026-09-21T17:27:57+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89732.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89732.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89732"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532293"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89732"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89732"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89732.mbox"},{"url":"https://git.kernel.org/stable/c/34e88f53614640b59039a46717fb6142e9871022"},{"url":"https://git.kernel.org/stable/c/569dd7e5dcffe1e1c6b26ca2cd3be57eb433e082"},{"url":"https://git.kernel.org/stable/c/eac233e63f9db82ba874e3cccafaafab162999e0"},{"url":"https://git.kernel.org/stable/c/fd20cc68bbdb5620696ac108e8f2efd180fe2c1a"},{"url":"https://git.kernel.org/stable/c/fbe3db4b650c284df8eb4cb68eebcf270cf861b5"},{"url":"https://git.kernel.org/stable/c/30430509c156e1df2bdafd5f1cadb160e53db5d6"},{"url":"https://git.kernel.org/stable/c/bafddd0f20b5228760be303aa69c58502e92309c"},{"url":"https://git.kernel.org/stable/c/b0a6bfac0c3c3edf5b2ecaee87a09234601fe78d"}],"tags":["csaf","vex","red-hat","cve.org"],"epss":0.00226,"epssPercentile":0.13616,"ingestedAt":"2026-09-14T15:23:07.449Z","slug":"CVE-2026-89732","body":"## Overview\n\nA flaw was found in the Linux kernel's USB FunctionFS (f_fs) module. A local attacker could exploit a deadlock vulnerability in the ffs_ep0_read() function. This occurs when a userspace daemon polls ep0 and the USB gadget is simultaneously torn down, causing the kernel to enter an unresponsive state. This can lead to a denial of service (DoS).\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89732.json)\n\n**kernel: usb: gadget: f_fs: Prevent deadlock during ep0 read loop** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-21.\n\nNot affected:\n\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 6\n- Red Hat Enterprise Linux 7\n- Red Hat Enterprise Linux 8\n- Red Hat Enterprise Linux 9\n- Red Hat OpenShift Container Platform 4\n\n## Remediation\n\nRefer to the advisory for fix availability.","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":208961,"id":"CVE-2026-89732","ts":1790062300360,"field":"cvss","old":"4.1","new":"5.5"},{"seq":204023,"id":"CVE-2026-89732","ts":1789490231089,"field":"cvss","old":null,"new":"4.1"},{"seq":204022,"id":"CVE-2026-89732","ts":1789490231089,"field":"severity","old":"none","new":"medium"},{"seq":147412,"id":"CVE-2026-89732","ts":1789270210808,"field":"cvss","old":null,"new":"4.1"},{"seq":147411,"id":"CVE-2026-89732","ts":1789270210808,"field":"severity","old":"none","new":"medium"},{"seq":109168,"id":"CVE-2026-89732","ts":1789183730578,"field":"cvss","old":null,"new":"4.1"},{"seq":109167,"id":"CVE-2026-89732","ts":1789183730578,"field":"severity","old":"none","new":"medium"}]}