CVE-2025-66019

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

• ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
• AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
• Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.38% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 32.5% of scored records. A rank, not a probability.

NVD base score

6.6 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS: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

NVD analysis status

Deferred. NVD last modified this record on 2026-10-19.

Red Hat severity

Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2025-11-25 23:38Z11 MO AGO

Last updated

2026-01-20 18:33Z9 MO AGO

Reserved

2025-11-21

Assigning CNA

GitHub_M

Record state

PUBLISHED

Severity

Medium (CVSS 6.6)

CNA CVSS vector

CVSS: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

Weaknesses

• CWE-400Uncontrolled Resource ConsumptionClass
• CWE-409Improper Handling of Highly Compressed Data (Data Amplification)Base
• CWE-770Allocation of Resources Without Limits or ThrottlingBase

Data version

5.2

Document digest

9faef25e2329056693aec1767b0158422a2a09cabf88c433624120d2e22ba504

• github.comhttps://github.com/py-pdf/pypdf/security/advisories/GHSA-m449-cwjh-6pw7x_refsource_CONFIRM
• github.comhttps://github.com/py-pdf/pypdf/commit/96186725e5e6f237129a58a97cd19204a9ce40b2x_refsource_MISC
• github.comhttps://github.com/py-pdf/pypdf/releases/tag/6.4.0x_refsource_MISC
• aydinnyunus.github.iohttps://aydinnyunus.github.io/2025/12/20/cve-2025-66019-pypdf-lzw-dos/