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.
CVE-2026-54651
This medium-severity CVE scores 5.5 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 98% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 5.5
- EG Score
- 5.5(medium)
- EPSS
- 1.6%
- KEV
- Not listed
Published
June 22, 2026
Last Modified
June 24, 2026
Advisory Details (3)
Auto-updated Jun 22, 2026Possible infinite loop when processing threads/articles in writer · Advisory · py-pdf/pypdf · GitHub
https://github.com/py-pdf/pypdf/security/advisories/GHSA-g9xf-7f8q-9mcjVersion 6.13.1, 2026-06-08
Patch available: py-pdf/pypdf 6.13.1
https://github.com/py-pdf/pypdf/releases/tag/6.13.1SEC: Prevent infinite loops when processing threads/articles
Patch available: py-pdf/pypdf 6.13.1 (PR #3839 merged 2026-06-08)
https://github.com/py-pdf/pypdf/pull/3839Vendor Advisories for CVE-2026-54651(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 20× in last 7d / 52× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-11 23:58 UTCEG score recompute
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-11 02:13 UTCEG score recompute
- 2026-07-10 04:27 UTCEG score recompute
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-09 06:37 UTCEG score recompute
- 2026-07-08 15:16 UTCEPSS rescore
- 2026-07-08 15:16 UTCEPSS rescore
- 2026-07-08 08:50 UTCEG score recompute
- 2026-07-07 13:46 UTCEPSS rescore
- 2026-07-07 13:46 UTCEPSS rescore
- 2026-07-07 11:05 UTCEG score recompute
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 12:33 UTCEG score recompute
- 2026-07-06 02:23 UTCEPSS rescore
- 2026-07-06 02:23 UTCEPSS rescore
- 2026-07-05 14:48 UTCEG score recompute
- 2026-07-05 02:31 UTCEPSS rescore
- 2026-07-05 02:30 UTCEPSS rescore
- 2026-07-04 16:51 UTCEG score recompute
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
Show 27 moreShow fewer
- 2026-07-03 18:54 UTCEG score recompute
- 2026-07-02 21:08 UTCEG score recompute
- 2026-07-01 23:22 UTCEG score recompute
- 2026-07-01 15:07 UTCEPSS rescore
- 2026-07-01 01:37 UTCEG score recompute
- 2026-06-30 23:22 UTCEPSS rescore
- 2026-06-30 03:51 UTCEG score recompute
- 2026-06-29 14:06 UTCEPSS rescore
- 2026-06-29 14:06 UTCEPSS rescore
- 2026-06-29 06:05 UTCEG score recompute
- 2026-06-28 14:07 UTCEPSS rescore
- 2026-06-28 08:16 UTCEG score recompute
- 2026-06-28 04:56 UTCEPSS rescore
- 2026-06-28 04:56 UTCEPSS rescore
- 2026-06-27 10:31 UTCEG score recompute
- 2026-06-27 03:08 UTCEPSS rescore
- 2026-06-26 12:45 UTCEG score recompute
- 2026-06-25 14:59 UTCEG score recompute▼ 1.40
- 2026-06-25 13:49 UTCEPSS rescore
- 2026-06-24 18:02 UTCNVD updateCVSS v3 → 5.5
- 2026-06-24 17:12 UTCEG score recompute
- 2026-06-24 14:05 UTCEPSS rescore
- 2026-06-23 21:33 UTCEPSS rescore
- 2026-06-23 21:33 UTCEPSS rescore
- 2026-06-23 19:24 UTCEG score recompute
- 2026-06-22 21:38 UTCEG score recompute
- 2026-06-22 21:37 UTCNVD updatefirst tracked
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Frequently asked(5)
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