{"id":"CVE-2023-36807","aliases":["GHSA-hm9v-vj3r-r55m","PYSEC-2026-1836"],"url":"https://o3.security/vulnerability/CVE-2023-36807","summary":"Infinite Loop when reading malformed objects in pypdf","details":"pypdf is a pure-python PDF library capable of splitting, merging, cropping, and transforming the pages of PDF files. In version 2.10.5 an attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This infinite loop blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. That is, for example, the case if the user extracted metadata from such a malformed PDF. Versions prior to 2.10.5 throw an error, but do not hang forever. This issue was fixed with https://github.com/py-pdf/pypdf/pull/1331 which has been included in release 2.10.6. Users are advised to upgrade. Users unable to upgrade should modify `PyPDF2/generic/_data_structures.py::read_object` to an an error throwing case. See GHSA-hm9v-vj3r-r55m for details. ","published":"2023-06-30T18:38:10.303Z","modified":"2026-07-15T01:49:03.524616647Z","cvss":{"score":6.2,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":2,"affectedPackages":[{"ecosystem":"PyPI","name":"pypdf2","fixedVersion":"2.10.6"}],"fix":{"url":"https://github.com/py-pdf/pypdf/pull/1331","label":"py-pdf/pypdf#1331"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/36xxx/CVE-2023-36807.json"},{"type":"ADVISORY","url":"https://github.com/py-pdf/pypdf/security/advisories/GHSA-hm9v-vj3r-r55m"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-36807"},{"type":"REPORT","url":"https://github.com/py-pdf/pypdf/issues/1329"},{"type":"FIX","url":"https://github.com/py-pdf/pypdf/pull/1331"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-15T01:49:03.524616647Z"}}