{"id":"CVE-2026-27026","aliases":["GHSA-9mvc-8737-8j8h","PYSEC-2026-3015"],"url":"https://o3.security/vulnerability/CVE-2026-27026","summary":"pypdf possibly has long runtimes for malformed FlateDecode streams","details":"### Impact\n\nAn attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a malformed `/FlateDecode` stream, where the byte-by-byte decompression is used.\n\n### Patches\n\nThis has been fixed in [pypdf==6.7.1](https://github.com/py-pdf/pypdf/releases/tag/6.7.1).\n\n### Workarounds\n\nIf you cannot upgrade yet, consider applying the changes from PR [#3644](https://github.com/py-pdf/pypdf/pull/3644).","published":"2026-02-20T21:12:33.537Z","modified":"2026-08-27T14:10:52.022987783Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"pypdf","fixedVersion":"6.7.1"}],"fix":{"url":"https://github.com/py-pdf/pypdf/commit/7905842d833f899f1d3228af7e7467ad80277016","label":"py-pdf/pypdf@7905842"},"references":[{"type":"WEB","url":"https://github.com/py-pdf/pypdf/releases/tag/6.7.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27026.json"},{"type":"ADVISORY","url":"https://github.com/py-pdf/pypdf/security/advisories/GHSA-9mvc-8737-8j8h"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27026"},{"type":"FIX","url":"https://github.com/py-pdf/pypdf/commit/7905842d833f899f1d3228af7e7467ad80277016"},{"type":"FIX","url":"https://github.com/py-pdf/pypdf/pull/3644"},{"type":"PACKAGE","url":"https://github.com/py-pdf/pypdf"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-27T14:10:52.022987783Z"}}