CVE-2026-41168CWE-834

pypdf has possible long runtimes for wrong size values in cross-reference and object streams

Medium · published April 22, 2026

CVSS v4.0
6.9
EPSS
1%
Percentile
43.0
In the wild
Unconfirmed
What it is

pypdf is a free and open-source pure-python PDF library. An attacker who uses a vulnerability present in versions prior to 6.10.1 can craft a PDF which leads to long runtimes. This requires cross-reference streams with wrong large `/Size` values or object streams with wrong large `/N` values. This has been fixed in pypdf 6.10.1. As a workaround, one may apply the changes from the patch manually.

The record
Technical detail
CVSS v4.0
6.9 · MEDIUM
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
EPSS
0.00515 · 43.0th percentile
Weakness
CWE-834 · Excessive Iteration
Published
2026-04-22T20:49Z
EPSS history
Timeline
  • 22 APR 20:49Z
    pypdf has possible long runtimes for wrong size values in cross-reference and object streams
    cvelistv5