What is CVE-2026-54531?

CVE-2026-54531 is a medium-severity vulnerability in Py-pdf Pypdf, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 5.5/10. Published 2026-06-22.

How severe is CVE-2026-54531?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Vulnerability in Py-pdf Pypdf

CVE-2026-54531

pypdf is a free and open-source pure-python PDF library. Prior to 6.13.0, an attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires merging a file with outlines into a writer. This vulnerability…

EPSS: 0.001 (2.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Affected products

Py-pdf Pypdf — versions < 6.13.0
Pypdf_project Pypdf

Weakness classification (CWE)

CWE-835 — Loop with Unreachable Exit Condition (Infinite Loop)

References

security-advisories@github.com (x_refsource_CONFIRM, Patch, Vendor Advisory)
security-advisories@github.com (Patch, x_refsource_MISC, Issue Tracking)
security-advisories@github.com (Patch, x_refsource_MISC, Release Notes)

Frequently asked questions

What is CVE-2026-54531?: CVE-2026-54531 is a medium-severity vulnerability in Py-pdf Pypdf, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 5.5/10. Published 2026-06-22.
How severe is CVE-2026-54531?: Medium severity. CVSS v3 base score is 5.5 out of 10.