TI-2026-65554 Aliases CVE-2026-102997 GHSA-jw7q-gvrg-4vj3

pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up)

LOW 38CWE-400Published 2026-09-30 · Updated 2026-10-02

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: 6 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 6.18.1, a crafted PDF containing a partially malformed /FlateDecode stream with padded data can force pypdf/filters.py to use inefficient byte-by-byte decompression while the earlier recovery counter fails to advance for bytes that successfully decode, causing long runtimes and application unavailability. This is a residual issue after the malformed FlateDecode recovery fix. This issue is fixed in version 6.18.1.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.0034 27th percentileScored 2026-11-07

Fix Partial pypdf (py-pdf): 6.18.1pypdf (PyPI): 6.18.1Red Hat: 6 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
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 6.18.1	6.18.1	Patch available	CNA
—	pypdf (PyPI)	before 6.18.1	6.18.1	Patch available	GHSA-jw7q-gvrg-4vj3

pypdf Vendorpy-pdf Affected before 6.18.1 Fixed in 6.18.1 Patch available CNA
pypdf (PyPI) Vendor— Affected before 6.18.1 Fixed in 6.18.1 Patch available GHSA-jw7q-gvrg-4vj3

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:py-pdf:pypdf::::::::	before 6.18.1	Vulnerable	py-pdf

cpe:2.3:a:py-pdf:pypdf:*:*:*:*:*:*:*:* Versions before 6.18.1 Vulnerable ·py-pdf

Remediation

Fix · CNA pypdf (py-pdf) Fixed in 6.18.1
Fix · GHSA-jw7q-gvrg-4vj3 pypdf (PyPI) Fixed in 6.18.1 Advisory →

Vendor assessments

Red Hat

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

Product	Status	Plan or fix
Ansible Automation Orchestrator 2026	Affected	No fix yet
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: 1 product

OpenShift Lightspeed

Timeline

2026-10-02 Threatist record created from CVE-2026-102997
2026-10-03 Alias added: GHSA-jw7q-gvrg-4vj3
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-2026-65557 pypdf: Possible large memory usage when retrieving alphabetical page labels CVSS 4.0HIGH 8.7
TI-2026-65556 pypdf: Possible long runtimes with large amount of embedded files 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