{"id":"CVE-2026-26054","summary":"SumatraPDF: Heap out-of-bounds read in MOBI header parser.","details":"SumatraPDF is a multi-format reader for Windows. Prior to 3.6, the MobiDoc::ParseHeader function in src/MobiDoc.cpp validates a record using kMobiHeaderMinLen but DecodeMobiDocHeader constructs a decoder sized for kMobiHeaderLen without receiving the actual remaining buffer length. A malformed MOBI file can use an attacker-controlled header length to bypass optional-field early returns and cause the decoder to read beyond a short heap buffer. Opening the crafted document can crash SumatraPDF. This issue is fixed in version 3.6.","aliases":["GHSA-27p6-wrfp-pgm8"],"modified":"2026-09-26T03:45:47.435077356Z","published":"2026-09-24T16:48:03.247Z","database_specific":{"cwe_ids":["CWE-125"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/26xxx/CVE-2026-26054.json","cna_assigner":"GitHub_M"},"references":[{"type":"WEB","url":"https://github.com/sumatrapdfreader/sumatrapdf/releases/tag/3.6rel"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/26xxx/CVE-2026-26054.json"},{"type":"ADVISORY","url":"https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-27p6-wrfp-pgm8"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-26054"},{"type":"REPORT","url":"https://github.com/sumatrapdfreader/sumatrapdf/issues/5318"},{"type":"FIX","url":"https://github.com/sumatrapdfreader/sumatrapdf/commit/24b9ce83383bbaa48b3efe00e4d30cccea126198"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/sumatrapdfreader/sumatrapdf","events":[{"introduced":"0"},{"fixed":"24b9ce83383bbaa48b3efe00e4d30cccea126198"},{"fixed":"b9732699d403ccb41f1135e0bd7f425c475e7689"}],"database_specific":{"source":["AFFECTED_FIELD","REFERENCES"],"extracted_events":[{"introduced":"0"},{"fixed":"3.6"}]}}],"versions":["3.2","3.1.2rel","3.0split","2.5split","2.4split","2.3split","2.2split","2.1split","2.0split","1.9split","1.8split","1.7split","1.6split","1.5split","1.4split"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-26054.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"}]}