CVE Tools
Sign in

CVE-2026-22691

pypdf has possible long runtimes for malformed startxref

Published: Jan 10, 2026Updated: Jan 22, 2026 Sources: CVE List NVD GHSA BDUCWE-400
5.3MEDIUM
NVD MITRE
EPSS Score
0.4%
Top 66.6%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
Not available

Description

pypdf is a free and open-source pure-python PDF library. Prior to version 6.6.0, pypdf has possible long runtimes for malformed startxref. An attacker who uses this vulnerability can craft a PDF which leads to possibly long runtimes for invalid startxref entries. When rebuilding the cross-reference table, PDF files with lots of whitespace characters become problematic. Only the non-strict reading mode is affected. Only the non-strict reading mode is affected. This issue has been patched in version 6.6.0.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:L
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:LAvailability
Low
Open in CVSS calculator →

Weaknesses

CWE-400CWE-1333

Affected Products

ООО «Ред Софт»
commercial·RUaka red soft
РЕД ОСOn-premOS
Operating Systems / linux-distro
Matthew Peveler
aka pypdf2
PyPDF2Library
OSS Libraries
pypdf project
oss-project
pypdfLibrary
OSS Libraries / generic-library
py-pdf
package-ecosystemaka pypdf2, pypdf
pypdfOn-prem
OSS Libraries / pypi
PyPI
package-ecosystem
pypdf
OSS Libraries

Exploitability

Official Patch Available

Attack Graph

Products CVE Techniques Tactics

Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.

MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

https://github.com/py-pdf/pypdf
github.com
https://github.com/py-pdf/pypdf/commit/294165726b646bb7799be1cc787f593f2fdbcf45
github.com
https://github.com/py-pdf/pypdf/pull/3594
github.com
and 9 more references View all →

Unlock Complete Vulnerability Intelligence

Get the full picture for CVE-2026-22691 and every CVE in our database. Create a free account — no credit card required.

Create Free Account
Plain-language analysis
Impact assessment and exploitation scenario in plain English
Attack graph visualization
Interactive attack path and kill chain mapping
Exploit details & PoC links
ExploitDB, Metasploit, GitHub PoCs with direct links
Nuclei scanner templates
Ready-to-use vulnerability scanner templates
Full remediation guide
Patch instructions, workarounds, and compliance impact
Interactive AI chat
Ask questions about this vulnerability in natural language
Related vulnerabilities
Semantically similar CVEs and attack patterns
REST API & MCP access
Integrate vulnerability data into your workflows