CVE-2026-33699: py-pdf pypdf Infinite Loop
Vulnerability summary
CVE-2026-33699 is a high (CVSS 7.5) Infinite Loop vulnerability in py-pdf pypdf. EPSS estimates a 0.58% chance of exploitation in the next 30 days, higher than 47.1% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 0 · Related 1Timeline
- 26-03-2026PublishedVulnerability first disclosed.
- 27-03-2026Last modifiedVulnerability information updated.
Description
pypdf is a free and open-source pure-python PDF library. Versions prior to 6.9.2 have a vulnerability in which an attacker can craft a PDF which leads to an infinite loop. This requires reading a file in non-strict mode. This has been fixed in pypdf 6.9.2. If users cannot upgrade yet, consider applying the changes from the patch manually.
CVSS metrics
9 scores · 7 sources · 2 versions- OSV · PypiEcosystem advisory · calculated8.2HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:UDiffers
- OSV · UbuntuEcosystem advisory · calculated8.2HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:UDiffers
- OSV · WolfiEcosystem advisory · calculated8.2HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:UDiffers
- OSV · ChainguardEcosystem advisory · calculated8.2HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:UDiffers
- NVDNIST4.6MediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/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 · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.58%
Chance of exploitation in the next 30 days
Percentile
47%
Versus all other CVEs
30-day change
+0.13 pp
From 0.46% on 21-09-2026
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) | < 6.9.2-1
- pypdf2All versions (No fix recorded)
Ubuntu2 products
- pypdfAll versions (No fix recorded)
- pypdf2All versions (No fix recorded)
Chainguard1 product
- open-webui< 0.8.12-r2 | < 0.8.12-r1
Opensuse1 product
- python-pypdf&distro=openSUSE Tumbleweed< 6.9.2-1.1
Py-pdf1 product
- pypdf< 6.9.2
Pypdf_project1 product
- pypdf< 6.9.2
PyPI1 product
- pypdf< 6.9.2
Wolfi1 product
- open-webui< 0.8.12-r2 | < 0.8.12-r1
8 vendors · 10 products
References
12 links- github.com/py-pdf/pypdf/security/advisories/GHSA-87mj-5ggw-8qc3X Refsource CONFIRMWEBREPORTAdvisoryPatchVendor Advisory
- github.com/py-pdf/pypdfPACKAGE
- pypi.org/project/pypdfPACKAGE
