GHSA-55h5-xmcq-c37v: pypdf: Possible long runtimes for repeated malformed cross-reference entries

mediumCVE-2026-59937

Impact An attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires cross-reference streams with repeated malformed cross-reference streams. Patches This has been fixed in pypdf==6.14.0. Workarounds If you cannot upgrade yet, consider applying the changes from PR #3887.

Details

Source: GitHub Security Advisories (INTL · database · site)
Severity: medium
Published: 2026-07-23
Last updated: 2026-07-23
Exploitation: Not in CISA KEV at last sync

Original advisory: https://github.com/advisories/GHSA-55h5-xmcq-c37v

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-599370.34% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 27% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-59937	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

highCVE-2026-59937: pypdf is a free and open-source pure-python PDF library. Prior to 6.14.0, an attacker can craf…nvd

GHSA-55h5-xmcq-c37v: pypdf: Possible long runtimes for repeated malformed cross-reference entries

Details

Exploitation outlook

Referenced CVEs

Same CVEs, other sources

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