CVE-2026-54651

pypdf: Possible infinite loop when processing threads/articles in writer

At a glance

Severity: MEDIUM 6.9
EPSS: EPSS 0.16 % · percentile 5 (2026-10-27)
State: PUBLISHED
Published: 2026-06-22
Updated: 2026-06-23
Assigner: GitHub_M
NVD status: Analyzed

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.13.1, an attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires merging a file with threads/articles into a writer. This vulnerability is fixed in 6.13.1.

Scores

Version	Score	Vector	Scored by
CVSS 4.0	MEDIUM 6.9	CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N	GitHub_M
CVSS 4.0	MEDIUM 6.9	CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X	NVD · security-advisories@github.com (Secondary)
CVSS 3.1	MEDIUM 5.5	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H	NVD · nvd@nist.gov (Primary)

Weaknesses (CWE)

CWE-835

Advisories

GHSA-g9xf-7f8q-9mcj — pypdf: Possible infinite loop when processing threads/articles in writer
PYSEC-2026-3018 — pypdf: Possible infinite loop when processing threads/articles in writer

European references

ENISA EUVD · EUVD-2026-38358
GCVE · GCVE-0-2026-54651

CERT-FR advisories

CERTFR-2026-AVI-1378 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
CERTFR-2026-AVI-1206 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
CERTFR-2026-AVI-0933 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr

Affected configurations (NVD CPE)

cpe:2.3:a:pypdf_project:pypdf:*:*:*:*:*:*:*:* < 6.13.1

Affected products

Product	Versions
py-pdf · pypdf	affected < 6.13.1

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD