TI-2026-56815 Aliases CVE-2026-82398 GHSA-fc8x-2rww-xw9m

pypdf: Inefficient handling of non-whitespace inputs in read_until_whitespace

LOW 37CWE-407Published 2026-08-31 · Updated 2026-09-01

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 · Low
Fix status: Partial Red Hat: 8 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-407.

Summary

pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, an attacker can craft a PDF that causes long runtimes when the pypdf/_utils.py function read_until_whitespace reads a stream containing a long run of bytes without whitespace. The function repeatedly performs immutable bytes concatenation in a one-byte loop, causing quadratic processing cost for the long non-whitespace input. This issue is fixed in version 6.15.0.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00524 44th percentileScored 2026-11-07

Fix Partial pypdf (py-pdf): 6.15.0pypdf (PyPI): 6.15.0Red Hat: 8 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 6.15.0	6.15.0	Patch available	CNA
—	pypdf (PyPI)	before 6.15.0	6.15.0	Patch available	GHSA-fc8x-2rww-xw9m

pypdf Vendorpy-pdf Affected before 6.15.0 Fixed in 6.15.0 Patch available CNA
pypdf (PyPI) Vendor— Affected before 6.15.0 Fixed in 6.15.0 Patch available GHSA-fc8x-2rww-xw9m

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:py-pdf:pypdf::::::::	before 6.15.0	Vulnerable	py-pdf

cpe:2.3:a:py-pdf:pypdf:*:*:*:*:*:*:*:* Versions before 6.15.0 Vulnerable ·py-pdf

Remediation

Fix · CNA pypdf (py-pdf) Fixed in 6.15.0
Fix · GHSA-fc8x-2rww-xw9m pypdf (PyPI) Fixed in 6.15.0 Advisory →

Vendor assessments

Red Hat

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

Product	Status	Plan or fix
Ansible Automation Orchestrator 2026	Affected	No fix yet: Fix deferred
Exploit Intelligence	Affected	No fix planned: Out of support scope
Lightspeed Core	Affected	No fix yet: Fix deferred
OpenShift Lightspeed	Affected	No fix yet: Fix deferred
Red Hat Ansible Automation Platform 2	Affected	No fix planned: Out of support scope
Red Hat Enterprise Linux AI (RHEL AI) 3	Affected	No fix yet: Fix deferred
Red Hat OpenShift AI (RHOAI)	Affected	No fix yet: Fix deferred
Red Hat Quay 3	Affected	No fix yet: Fix deferred

Timeline

2026-10-02 Threatist record created from CVE-2026-82398
2026-10-03 Alias added: GHSA-fc8x-2rww-xw9m
2026-10-05 CVSS score added · NVD

References

Patch 3

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-82398

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