{"id":"CVE-2026-89726","title":"lib/ucs2_string.c: fix out-of-bounds read in ucs2_strnlen()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nlib/ucs2_string.c: fix out-of-bounds read in ucs2_strnlen()\n\nPatch series \"lib/ucs2_string.c: fix out-of-bounds read in\nucs2_strnlen()\", v2.\n\nThis series fixes an off-b…","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-125"],"vendor":"Linux","product":"Linux","affected":["Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 04ae68af4107600120c3c41c94268f43bc350d48","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 2e5a70a175f0c74e7238b013a96c4eabc3002934","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3ada20e110bf3245edb0a3bcddadc33d0f142f8d","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 60c74f42f5abddb85dd919b4448d5474e65dbe76","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 709eb41adaf78d59d4579a13a898125919b69bcc","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 7d658da725ea81c91f73087547b97e7ced82d62b","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 1b0dc3cbb8630f0b5cb34d848628225920a904be","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < cec0d03fe785380540dc1b4d07c80f67ae2ffc78","Linux 2.6.12"],"published":"2026-09-11","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:51:39.437Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89726","references":[{"url":"https://git.kernel.org/stable/c/04ae68af4107600120c3c41c94268f43bc350d48"},{"url":"https://git.kernel.org/stable/c/2e5a70a175f0c74e7238b013a96c4eabc3002934"},{"url":"https://git.kernel.org/stable/c/3ada20e110bf3245edb0a3bcddadc33d0f142f8d"},{"url":"https://git.kernel.org/stable/c/60c74f42f5abddb85dd919b4448d5474e65dbe76"},{"url":"https://git.kernel.org/stable/c/709eb41adaf78d59d4579a13a898125919b69bcc"},{"url":"https://git.kernel.org/stable/c/7d658da725ea81c91f73087547b97e7ced82d62b"},{"url":"https://git.kernel.org/stable/c/1b0dc3cbb8630f0b5cb34d848628225920a904be"},{"url":"https://git.kernel.org/stable/c/cec0d03fe785380540dc1b4d07c80f67ae2ffc78"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89726.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89726"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532261"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89726"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89726"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89726.mbox"}],"tags":["cve.org","csaf","vex","red-hat"],"epss":0.00177,"epssPercentile":0.07238,"ingestedAt":"2026-09-14T15:23:07.449Z","slug":"CVE-2026-89726","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nlib/ucs2_string.c: fix out-of-bounds read in ucs2_strnlen()\n\nPatch series \"lib/ucs2_string.c: fix out-of-bounds read in\nucs2_strnlen()\", v2.\n\nThis series fixes an off-by-one out-of-bounds read in ucs2_strnlen().\n\nThe first patch is the real fix, the second patch comes as a bonus and\nfixes the code indentation.\n\n\nThis patch (of 2):\n\nucs2_strnlen() checks the current character before checking whether the\ncaller-provided maximum length has been reached.  If the input is not\nNUL-terminated within that bound, the loop can read one ucs2_char_t past\nthe limit.\n\nTest the length before dereferencing to prevent an off-by-one\nout-of-bounds read.\n\n## Affected\n\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 04ae68af4107600120c3c41c94268f43bc350d48`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 2e5a70a175f0c74e7238b013a96c4eabc3002934`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3ada20e110bf3245edb0a3bcddadc33d0f142f8d`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 60c74f42f5abddb85dd919b4448d5474e65dbe76`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 709eb41adaf78d59d4579a13a898125919b69bcc`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 7d658da725ea81c91f73087547b97e7ced82d62b`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 1b0dc3cbb8630f0b5cb34d848628225920a904be`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < cec0d03fe785380540dc1b4d07c80f67ae2ffc78`\n- `Linux 2.6.12`\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 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, … · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89726.json)","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":208963,"id":"CVE-2026-89726","ts":1790062301025,"field":"cvss","old":"5.3","new":"5.5"},{"seq":204027,"id":"CVE-2026-89726","ts":1789490231107,"field":"cvss","old":null,"new":"5.3"},{"seq":204026,"id":"CVE-2026-89726","ts":1789490231107,"field":"severity","old":"none","new":"medium"},{"seq":147472,"id":"CVE-2026-89726","ts":1789270211042,"field":"cvss","old":null,"new":"5.3"},{"seq":147471,"id":"CVE-2026-89726","ts":1789270211042,"field":"severity","old":"none","new":"medium"},{"seq":109228,"id":"CVE-2026-89726","ts":1789183731025,"field":"cvss","old":null,"new":"5.3"},{"seq":109227,"id":"CVE-2026-89726","ts":1789183731025,"field":"severity","old":"none","new":"medium"}]}