pypdf is a free and open-source pure-python PDF library. Prior to 6.21.3, pypdf can take excessive time to retrieve page labels from a crafted PDF containing a flat page-label number tree with many ranges. The page_labels property resolves each page independently and repeatedly scans the same /Nums array from the beginning, causing work to grow with both the page count and the number of label ranges. This issue is fixed in version 6.21.3.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 1
- First seenCVSS 7.1 · py-pdfNVD modified 2026-10-29 20:37
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 4
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-42gh-23hr-vphw x_refsource_confirm
- https://github.com/py-pdf/pypdf/pull/4251 x_refsource_misc
- https://github.com/py-pdf/pypdf/commit/b891fef37000cd86baa6e9848a3387d080b3b03e x_refsource_misc
- https://github.com/py-pdf/pypdf/releases/tag/6.21.3 x_refsource_misc