TI-2026-65557 Aliases CVE-2026-103000 GHSA-w23x-9jrw-r45c

pypdf: Possible large memory usage when retrieving alphabetical page labels

MEDIUM 44CWE-400Published 2026-09-30 · Updated 2026-09-30

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: None
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Partial Red Hat: 5 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-400.

Summary

pypdf is a free and open-source pure-python PDF library. Prior to 6.19.0, a crafted PDF can provide unusually large alphabetical page-label values that cause pypdf/_page_labels.py to generate strings beyond a reasonable page-label length when an application retrieves document page labels, consuming excessive memory and potentially making the application unavailable. This issue is fixed in version 6.19.0.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00352 29th percentileScored 2026-11-07

Fix Partial pypdf (py-pdf): 6.19.0pypdf (PyPI): 6.19.0Red Hat: 5 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
py-pdf	pypdf	before 6.19.0	6.19.0	Patch available	CNA
—	pypdf (PyPI)	before 6.19.0	6.19.0	Patch available	GHSA-w23x-9jrw-r45c

pypdf Vendorpy-pdf Affected before 6.19.0 Fixed in 6.19.0 Patch available CNA
pypdf (PyPI) Vendor— Affected before 6.19.0 Fixed in 6.19.0 Patch available GHSA-w23x-9jrw-r45c

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:py-pdf:pypdf::::::::	before 6.19.0	Vulnerable	py-pdf

cpe:2.3:a:py-pdf:pypdf:*:*:*:*:*:*:*:* Versions before 6.19.0 Vulnerable ·py-pdf

Remediation

Fix · CNA pypdf (py-pdf) Fixed in 6.19.0
Fix · GHSA-w23x-9jrw-r45c pypdf (PyPI) Fixed in 6.19.0 Advisory →

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

Product	Status	Plan or fix
Lightspeed Core	Affected	No fix yet
Red Hat Ansible Automation Platform 2	Affected	No fix planned: Will not fix
Red Hat Enterprise Linux AI (RHEL AI) 3	Affected	No fix yet
Red Hat OpenShift AI (RHOAI)	Affected	No fix yet
Red Hat Quay 3	Affected	No fix yet

Not affected: 2 products

Ansible Automation Orchestrator 2026
OpenShift Lightspeed

Timeline

2026-10-02 Threatist record created from CVE-2026-103000
2026-10-03 Alias added: GHSA-w23x-9jrw-r45c
2026-10-05 CVSS score added · NVD

References

Patch 2

Advisory 2

Other 2

TI-2023-18601 Infinite Loop when reading malformed objects in pypdf CVSS 3.1MEDIUM 6.5
TI-2023-18305 Infinite Loop when a comment isn't followed by a character in pypdf CVSS 3.1MEDIUM 6.2
TI-2026-42743 pypdf: Possible infinite loop for not terminated inline images CVSS 4.0HIGH 8.7
TI-2026-42742 pypdf: Possible infinite loop for not terminated inline images (ASCII85 and ASCIIHex filter) CVSS 4.0HIGH 8.7
TI-2026-65556 pypdf: Possible long runtimes with large amount of embedded files CVSS 4.0HIGH 8.7
TI-2026-65555 pypdf: Possible long runtimes when generating appearance streams CVSS 4.0HIGH 8.7

See all 65 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences