CVE-2025-55197

pypdf's Manipulated FlateDecode streams can exhaust RAM

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.

Category

6.6
CVSS
Severity: Medium
CVSS 4.0 •
CVSS 3.1 •
EPSS 0.04%
Third-Party Advisory github.com
Affected: py-pdf pypdf
Published at:
Updated at:

References

Link Tags
https://github.com/py-pdf/pypdf/security/advisories/GHSA-7hfw-26vp-jp8m third party advisory mitigation
https://github.com/py-pdf/pypdf/issues/3429 issue tracking
https://github.com/py-pdf/pypdf/pull/3430 patch
https://github.com/py-pdf/pypdf/blob/0dd57738bbdcdb63f0fb43d8a6b3d222b6946595/pypdf/filters.py#L72-L143 product
https://github.com/py-pdf/pypdf/releases/tag/6.0.0 release notes

Frequently Asked Questions

What is the severity of CVE-2025-55197?
CVE-2025-55197 has been scored as a medium severity vulnerability.
How to fix CVE-2025-55197?
To fix CVE-2025-55197, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2025-55197 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2025-55197 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-55197?
CVE-2025-55197 affects py-pdf pypdf.
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