{"id":"PYSEC-2026-1834","summary":"Possible Infinite Loop when PdfWriter(clone_from) is used with a PDF","details":"### Impact\nAn attacker who uses this vulnerability can craft a PDF which leads to an infinite loop.\nThis infinite loop blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage.\n\nThat is, for example, the case when the pypdf-user manipulates an incoming malicious PDF e.g. by merging it with another PDF or by adding annotations.\n\n### Patches\nThe issue was fixed with #2264\n\n### Workarounds\nIf you cannot update your version of pypdf, you should modify `pypdf/generic/_data_structures.py` just like #2264 did.","aliases":["CVE-2023-46250","GHSA-wjcc-cq79-p63f"],"modified":"2026-07-07T17:47:08.471731964Z","published":"2026-07-07T11:45:26.634787Z","references":[{"type":"WEB","url":"https://github.com/py-pdf/pypdf/security/advisories/GHSA-wjcc-cq79-p63f"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-46250"},{"type":"WEB","url":"https://github.com/py-pdf/pypdf/pull/2264"},{"type":"WEB","url":"https://github.com/py-pdf/pypdf/commit/9b23ac3c9619492570011d551d521690de9a3e2d"},{"type":"PACKAGE","url":"https://github.com/py-pdf/pypdf"},{"type":"PACKAGE","url":"https://pypi.org/project/pypdf"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-wjcc-cq79-p63f"}],"affected":[{"package":{"name":"pypdf","ecosystem":"PyPI","purl":"pkg:pypi/pypdf"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.7.0"},{"fixed":"3.17.0"}]}],"versions":["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","3.7.0","3.7.1","3.8.0","3.8.1","3.9.0","3.9.1"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/pypdf/PYSEC-2026-1834.yaml"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}