pypdf possibly loops infinitely when reading DCT inline images without EOF marker

Description

Impact

An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires parsing the content stream of a page which has an inline image using the DCTDecode filter.

Patches

This has been fixed in pypdf==6.1.3.

Workarounds

If you cannot upgrade yet, consider applying the changes from PR #3501.

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2025-10-22 19:40:47 UTC
Updated
2025-10-23 17:40:38 UTC
GitHub reviewed
2025-10-22 19:40:47 UTC
NVD published
2025-10-22

EPSS Score

Score Percentile
0.05% 14.35%

CVSS Scores

Base score Version Severity Vector
6.6 4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:N)
No privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:N)
No confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:N)
No integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:H)
High availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.
Exploit maturity (threat) (E:U)
Unreported: no public PoC, no reported exploitation, and no known simplification tools.

Identifiers

CWEs

CWE id Name
CWE-834 Excessive Iteration

Credits

  • tylzh97 (reporter)
  • stefan6419846 (analyst)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
pip pypdf < 6.1.3 6.1.3

References

cvelogic Threat Intelligence