{"id":"CVE-2026-26825","title":"A use-of-uninitialized memory vulnerability exists in libxls 1.6.3 when parsing malformed XLS files","summary":"A use-of-uninitialized memory vulnerability exists in libxls 1.6.3 when parsing malformed XLS files. The issue is reachable via xls_parseWorkBook() and is triggered by uninitialized heap memory originating from the OLE layer (ole2_read).…","severity":"medium","cvss":5.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","cwe":["CWE-908"],"vendor":"libxls_project","product":"libxls","affected":["libxls = 1.6.3"],"published":"2026-06-03","updated":"2026-09-23","sourceUpdated":"2026-09-23T16:16:42.607","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-26825","references":[{"url":"https://github.com/libxls/libxls/commit/9adf88f4e3b304e397f70ac189e70776edb6d5a3","label":"cve@mitre.org"},{"url":"https://github.com/libxls/libxls/issues/153","label":"cve@mitre.org"},{"url":"https://github.com/libxls/libxls/issues/156","label":"cve@mitre.org"}],"tags":["nvd","cve.org"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-06-08T16:41:53.848420Z"},"epss":0.00214,"epssPercentile":0.12057,"ingestedAt":"2026-09-23T16:27:22.624Z","slug":"CVE-2026-26825","body":"## Overview\n\nA use-of-uninitialized memory vulnerability exists in libxls 1.6.3 when parsing malformed XLS files. The issue is reachable via xls_parseWorkBook() and is triggered by uninitialized heap memory originating from the OLE layer (ole2_read). The flaw is detectable with MemorySanitizer (MSAN) and can lead to undefined behavior, incorrect parsing logic, or potential information disclosure.\n\n## Affected\n\n- `libxls = 1.6.3`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":29,"depthScoreParts":{"impact":29.2,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}