Intel

AIKIDO-2026-150856

pypdf is vulnerable to Denial of Service (DoS)

Denial of Service (DoS)GHSA-fp3f-mc75-235c Published Aug 10, 2026

48

Medium Risk

This Affects:

PYTHONpypdf
0.0.1 - 6.14.2
Fixed in 6.15.0
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TL;DR

pypdf parses /ToUnicode CMap streams when extracting text from a PDF. A crafted font can provide /ToUnicode entries with unusually large token values. Processing these entries consumes excessive memory while building the character map. The fix limits the token length accepted for /ToUnicode entries.

Who does this affect?

You are affected if you are using a version that falls within the vulnerable range and you extract text from PDF documents whose embedded fonts can carry an untrusted /ToUnicode CMap.

Background info

pypdf is vulnerable to Denial of Service (DoS) in versions 0.0.1 - 6.14.2.

How to fix this

Upgrade the pypdf library to the patch version.