CVE-2026-41312: pypdf — Fix

Description

pypdf is a free and open-source pure-python PDF library. An attacker who uses a vulnerability present in versions prior to 6.10.2 can craft a PDF which leads to the RAM being exhausted. This requires accessing a stream compressed using `/FlateDecode` with a `/Predictor` unequal 1 and large predictor parameters. This has been fixed in pypdf 6.10.2. As a workaround, one may apply the changes from the patch manually.

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CVSS v3.1 Score

6.5

MEDIUM

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

EPSS — Exploit Prediction

0.0002

Probability of exploitation

0.06%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-789 CWE-789

Affected Products

Vendor	Product	Versions
pypdf_project	pypdf	< 6.10.2

References

Advisories & Patches

https://github.com/py-pdf/pypdf/commit/ac734dab4eef92bcce50d503949b4d9887d89f11 https://github.com/py-pdf/pypdf/pull/3734 https://github.com/py-pdf/pypdf/security/advisories/GHSA-7gw9-cf7v-778f

Other References

https://github.com/py-pdf/pypdf/releases/tag/6.10.2

Frequently Asked Questions

What is CVE-2026-41312? +

pypdf is a free and open-source pure-python PDF library. An attacker who uses a vulnerability present in versions prior to 6.10.2 can craft a PDF which leads to the RAM being exhausted. This requires accessing a stream compressed using `/FlateDecode` with a `/Predictor` unequal 1 and large predictor parameters. This has been fixed in pypdf 6.10.2. As a workaround, one may apply the changes from the patch manually. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-41312? +

CVE-2026-41312 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0002, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-41312? +

CVE-2026-41312 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-2026-41312? +

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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