CVE-2026-84309: py-pdf pypdf Infinite Loop
Vulnerability summary
CVE-2026-84309 is a medium (CVSS 6.9) Infinite Loop vulnerability in py-pdf pypdf. EPSS estimates a 0.19% chance of exploitation in the next 30 days, higher than 7.7% of scored vulnerabilities.
Timeline
- 01-09-2026PublishedVulnerability first disclosed.
- 02-09-2026Last modifiedVulnerability information updated.
Description
pypdf is a free and open-source pure-python PDF library. Prior to 6.16.0, an attacker can craft a PDF whose cyclic tree structure causes pypdf/generic/_data_structures.py TreeObject.insert_child to follow /Next links indefinitely when a writing code path inserts a child, producing an infinite loop. This issue is fixed in version 6.16.0.
CVSS metrics
9 scores · 7 sources · 2 versions- OSV · PypiEcosystem advisory · calculated6.9MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- OSV · UbuntuEcosystem advisory · calculated6.9MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- OSV · WolfiEcosystem advisory · calculated6.9MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- OSV · ChainguardEcosystem advisory · calculated6.9MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- NVDNIST6.9MediumCVSS: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
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- NVDNIST5.5MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.19%
Chance of exploitation in the next 30 days
Percentile
8%
Versus all other CVEs
30-day change
+0.06 pp
From 0.13% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Debian2 products
- pypdfAll versions (No fix recorded) | < 6.19.0-1
- pypdf2All versions (No fix recorded)
Chainguard1 product
- open-webui< 0.11.3-r4
Opensuse1 product
- python-pypdf&distro=openSUSE Tumbleweed< 6.16.2-3.1
Py-pdf1 product
- pypdf< 6.16.0
Pypdf_project1 product
- pypdf< 6.16.0
PyPI1 product
- pypdf< 6.16.0
Ubuntu1 product
- pypdfAll versions (No fix recorded)
Wolfi1 product
- open-webui< 0.11.3-r4
8 vendors · 9 products
References
13 links- github.com/py-pdf/pypdf/security/advisories/GHSA-jp53-mhqp-8xcgX Refsource CONFIRMWEBAdvisoryPatchVendor Advisory
- github.com/py-pdf/pypdfPACKAGE
- pypi.org/project/pypdfPACKAGE
