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TI-2025-34873 Aliases CVE-2025-55197GHSA-7hfw-26vp-jp8m

pypdf's Manipulated FlateDecode streams can exhaust RAM

Priority LOW 36CWE-400Published · Updated

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: 2 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 version 6.0.0, an attacker can craft a PDF which leads to the RAM being exhausted. This requires just reading the file if a series of FlateDecode filters is used on a malicious cross-reference stream. Other content streams are affected on explicit access. This issue has been fixed in 6.0.0. If an update is not possible, a workaround involves including the fixed code from pypdf.filters.decompress into the existing filters file.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00507 43rd percentileScored 2026-11-07
Fix Partial pypdf (py-pdf): 6.0.0pypdf (PyPI): 6.0.0Red Hat: 2 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

VendorProductAffected versionsFixed inStatusSource
py-pdfpypdfbefore 6.0.06.0.0Patch availableCNA
—pypdf (PyPI)before 6.0.06.0.0Patch availableGHSA-7hfw-26vp-jp8m
  • pypdf Vendorpy-pdf Affected before 6.0.0 Fixed in 6.0.0 Patch available CNA
  • pypdf (PyPI) Vendor— Affected before 6.0.0 Fixed in 6.0.0 Patch available GHSA-7hfw-26vp-jp8m

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:py-pdf:pypdf:*:*:*:*:*:*:*:*before 6.0.0Vulnerablepy-pdf
  • cpe:2.3:a:py-pdf:pypdf:*:*:*:*:*:*:*:* Versions before 6.0.0 Vulnerable ·py-pdf

Remediation

  • Fix · CNA pypdf (py-pdf) Fixed in 6.0.0
  • Fix · GHSA-7hfw-26vp-jp8m pypdf (PyPI) Fixed in 6.0.0 Advisory →

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
OpenShift LightspeedAffectedNo fix yet: Fix deferred
Red Hat Ansible Automation Platform 2AffectedNo fix yet: Fix deferred

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-55197
  2. 2026-10-03 Alias added: GHSA-7hfw-26vp-jp8m

References

Patch 1

Advisory 2

Other 4

  • 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