{"id":"CVE-2026-33123","aliases":["GHSA-qpxp-75px-xjcp","PYSEC-2026-3023"],"title":"pypdf has inefficient decoding of array-based streams","summary":"pypdf has inefficient decoding of array-based streams","severity":"medium","vendor":"pypdf","product":"pypdf","ecosystem":"pip","affected":["pypdf < 6.9.1"],"patched":["pypdf 6.9.1"],"published":"2026-03-18","updated":"2026-09-10","sourceUpdated":"2026-09-10T03:51:00.643708515Z","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/GHSA-qpxp-75px-xjcp","references":[{"url":"https://github.com/py-pdf/pypdf/security/advisories/GHSA-qpxp-75px-xjcp"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33123"},{"url":"https://github.com/py-pdf/pypdf/pull/3686"},{"url":"https://github.com/py-pdf/pypdf"},{"url":"https://github.com/py-pdf/pypdf/releases/tag/6.9.1"}],"tags":["osv","pip"],"epss":0.00349,"epssPercentile":0.28629,"ingestedAt":"2026-07-13T18:58:02.180Z","slug":"CVE-2026-33123","body":"## Overview\n\n### Impact\nAn attacker who uses this vulnerability can craft a PDF which leads to long runtimes and/or large memory usage. This requires accessing an array-based stream with lots of entries.\n\n### Patches\nThis has been fixed in [pypdf==6.9.1](https://github.com/py-pdf/pypdf/releases/tag/6.9.1).\n\n### Workarounds\nIf you cannot upgrade yet, consider applying the changes from PR [#3686](https://github.com/py-pdf/pypdf/pull/3686).\n\n## Affected packages\n\n- `pypdf < 6.9.1`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `pypdf 6.9.1`","depth":"sunlit","depthScore":28,"depthScoreParts":{"impact":27.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}