How severe is CVE-2025-66019?

CVE-2025-66019 has a CVSS 4.0 base score of 6.6, rated medium severity.

Is CVE-2025-66019 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2025-66019?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-66019 have an EU (EUVD) identifier?

Yes. CVE-2025-66019 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-199017.

When was CVE-2025-66019 published?

CVE-2025-66019 was published on 2025-11-26 and last updated on 2026-06-17.

CVE-2025-66019

CVE-2025-66019 is a medium-severity vulnerability with a CVSS 4.0 base score of 6.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-400.

Key facts

Severity: Medium (CVSS 4.0 base score 6.6)
EPSS exploit prediction: 0% (23rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-199017
Weakness: CWE-400
Published: 2025-11-26
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2025-66019?: 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.
How severe is CVE-2025-66019?: CVE-2025-66019 has a CVSS 4.0 base score of 6.6, rated medium severity.
Is CVE-2025-66019 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-66019?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-66019 have an EU (EUVD) identifier?: Yes. CVE-2025-66019 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-199017.
When was CVE-2025-66019 published?: CVE-2025-66019 was published on 2025-11-26 and last updated on 2026-06-17.

References

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