CVE-2025-55197: pypdf DoS — Fix

Description

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.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-400 Uncontrolled Resource Consumption

CWE-770 CWE-770

Affected Products

Vendor	Product	Versions
pypdf_project	pypdf	< 6.0.0

References

Advisories & Patches

https://github.com/py-pdf/pypdf/pull/3430

Other References

https://github.com/py-pdf/pypdf/blob/0dd57738bbdcdb63f0fb43d8a6b3d222b6946595/pypdf/filters.py#L72-L143 https://github.com/py-pdf/pypdf/issues/3429 https://github.com/py-pdf/pypdf/releases/tag/6.0.0 https://github.com/py-pdf/pypdf/security/advisories/GHSA-7hfw-26vp-jp8m

Frequently Asked Questions

What is CVE-2025-55197? +

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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2025-55197? +

CVE-2025-55197 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-55197? +

CVE-2025-55197 affects products from pypdf_project, specifically: pypdf. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-55197? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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