CVE-2025-66019: py-pdf pypdf Uncontrolled Resource Consumption
Vulnerability summary
CVE-2025-66019 is a medium (CVSS 6.6) Uncontrolled Resource Consumption vulnerability in py-pdf pypdf. EPSS estimates a 0.36% chance of exploitation in the next 30 days, higher than 28.4% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 0 · Related 1Timeline
- 25-11-2025PublishedVulnerability first disclosed.
- 20-01-2026Last modifiedVulnerability information updated.
Description
pypdf is a free and open-source pure-python PDF library. Prior to version 6.4.0, an attacker who uses this vulnerability can craft a PDF which leads to a memory usage of up to 1 GB per stream. This requires parsing the content stream of a page using the LZWDecode filter. This issue has been patched in version 6.4.0.
CVSS metrics
6 scores · 6 sources · 1 version- OSV · PypiEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:UDiffers
- OSV · UbuntuEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:UDiffers
- OSV · WolfiEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:UDiffers
- OSV · ChainguardEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:UDiffers
- NVDNIST6.6MediumCVSS:4.0/AV:N/AC:L/AT:N/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
EPSS trend
Probability
0.36%
Chance of exploitation in the next 30 days
Percentile
28%
Versus all other CVEs
30-day change
0.00 pp
From 0.36% 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 cause- CWE-400Uncontrolled Resource ConsumptionThe product does not properly control the allocation and maintenance of a limited resource.
- CWE-409Improper Handling of Highly Compressed Data (Data Amplification)The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output.
Affected systems
Chainguard2 products
- nemo< 2.5.3-r1
- open-webui-compat< 0.6.40-r0
Opensuse1 product
- python-pypdf&distro=openSUSE Tumbleweed< 6.4.0-1.1
Py-pdf1 product
- pypdf< 6.4.0
PyPI1 product
- pypdf< 6.4.0
Ubuntu1 product
- pypdfAll versions (No fix recorded)
Wolfi1 product
- open-webui-compat< 0.6.40-r0
6 vendors · 7 products
References
14 links
- github.com/py-pdf/pypdfPACKAGE
- pypi.org/project/pypdfPACKAGE