Resource exhaustion in Py-Pdf Pypdf

CVE-2026-119206

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.

Vulnerability class: DoS (Denial of Service)

Published .

EPSS exploit prediction

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Affected products

Weakness classification (CWE)

References