{"id":"PYSEC-2026-3655","summary":"pypdf: Possible large memory usage for large /ToUnicode streams","details":"### Impact\n\nAn attacker who uses this vulnerability can craft a PDF which leads to large memory consumption. This requires parsing the `/ToUnicode` entry of a font with unusually large values, for example during text extraction.\n\n### Patches\n\nThis has been fixed in [pypdf==6.15.0](https://github.com/py-pdf/pypdf/releases/tag/6.15.0).\n\n### Workarounds\n\nIf you cannot upgrade yet, consider applying the changes from PR [#3944](https://github.com/py-pdf/pypdf/pull/3944).","aliases":["CVE-2026-71870","GHSA-fp3f-mc75-235c"],"modified":"2026-08-10T11:30:12.871465923Z","published":"2026-08-10T10:43:51.717413Z","references":[{"type":"WEB","url":"https://github.com/py-pdf/pypdf/security/advisories/GHSA-fp3f-mc75-235c"},{"type":"WEB","url":"https://github.com/py-pdf/pypdf/pull/3944"},{"type":"WEB","url":"https://github.com/py-pdf/pypdf/commit/afba8080e19d29a3c256a742b340995e695b35aa"},{"type":"PACKAGE","url":"https://github.com/py-pdf/pypdf"},{"type":"WEB","url":"https://github.com/py-pdf/pypdf/releases/tag/6.15.0"},{"type":"PACKAGE","url":"https://pypi.org/project/pypdf"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-fp3f-mc75-235c"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-71870"}],"affected":[{"package":{"name":"pypdf","ecosystem":"PyPI","purl":"pkg:pypi/pypdf"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.15.0"}]}],"versions":["1.0","1.1","1.10","1.11","1.12","1.13","1.2","1.3","1.4","1.5","1.6","1.7","1.8","1.9","3.1.0","3.10.0","3.11.0","3.11.1","3.12.0","3.12.1","3.12.2","3.13.0","3.14.0","3.15.0","3.15.1","3.15.2","3.15.3","3.15.4","3.15.5","3.16.0","3.16.1","3.16.2","3.16.3","3.16.4","3.17.0","3.17.1","3.17.2","3.17.3","3.17.4","3.2.0","3.2.1","3.3.0","3.4.0","3.4.1","3.5.0","3.5.1","3.5.2","3.6.0","3.7.0","3.7.1","3.8.0","3.8.1","3.9.0","3.9.1","4.0.0","4.0.1","4.0.2","4.1.0","4.2.0","4.3.0","4.3.1","5.0.0","5.0.1","5.1.0","5.2.0","5.3.0","5.3.1","5.4.0","5.5.0","5.6.0","5.6.1","5.7.0","5.8.0","5.9.0","6.0.0","6.1.0","6.1.1","6.1.2","6.1.3","6.10.0","6.10.1","6.10.2","6.11.0","6.12.0","6.12.1","6.12.2","6.13.0","6.13.1","6.13.2","6.13.3","6.14.0","6.14.1","6.14.2","6.2.0","6.3.0","6.4.0","6.4.1","6.4.2","6.5.0","6.6.0","6.6.1","6.6.2","6.7.0","6.7.1","6.7.2","6.7.3","6.7.4","6.7.5","6.8.0","6.9.0","6.9.1","6.9.2"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/pypdf/PYSEC-2026-3655.yaml"}}],"schema_version":"1.8.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"}]}