{"id":"CVE-2026-79591","title":"A heap-buffer-overflow and use-after-free vulnerability exists in the xls_getCSS() function of libxls 1.6.3 due to insufficient validation of a file-controlled font index.","summary":"A heap-buffer-overflow and use-after-free vulnerability exists in the xls_getCSS() function of libxls 1.6.3 due to insufficient validation of a file-controlled font index.","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","cwe":["CWE-122"],"published":"2026-09-10","updated":"2026-09-22","sourceUpdated":"2026-09-22T20:00:03.713","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-79591","references":[{"url":"https://github.com/libxls/libxls/issues/161","label":"cve@mitre.org"},{"url":"https://github.com/libxls/libxls/pull/164/changes/902c8f9b13710c3a13b6232fb86626c5c729402c","label":"cve@mitre.org"},{"url":"https://github.com/libxls/libxls/issues/161","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"tags":["nvd","cve.org","exploit-available"],"epss":0.00127,"epssPercentile":0.02679,"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"total","timestamp":"2026-09-15T14:09:00.571356Z"},"ingestedAt":"2026-09-11T16:45:48.024Z","slug":"CVE-2026-79591","body":"## Overview\n\nA heap-buffer-overflow and use-after-free vulnerability exists in the xls_getCSS() function of libxls 1.6.3 due to insufficient validation of a file-controlled font index.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":55,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":12,"ransomware":0},"changes":[{"seq":203716,"id":"CVE-2026-79591","ts":1789483138425,"field":"exploit_available","old":"false","new":"true"},{"seq":203715,"id":"CVE-2026-79591","ts":1789483138425,"field":"cvss","old":null,"new":"7.8"},{"seq":203714,"id":"CVE-2026-79591","ts":1789483138425,"field":"severity","old":"none","new":"high"}]}