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Vulnerabilities

Vulnerability · CVE-2025-66019

pypdf is a free and open-source pure-python PDF library.

Published Nov 25, 2025 · catalog updated Jan 20, 2026 · pypdf is a free

Last checked Nov 5, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2025-66019. EPSS is 0.39%. Act only if a listed version of pypdf is a free is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (pypdf is a free).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium6.6
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.39%
Remediation
Version ranges on file
Affected products
vendor py-pdf pypdf < 6.4.0

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor py-pdf pypdf < 6.4.0< 6.4.0

How to fix CVE-2025-66019

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-66019. EPSS is 0.39%. Act only if a listed version of pypdf is a free is installed.

Which versions are affected?

Compare what you have installed with py-pdf pypdf < 6.4.0 < 6.4.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.39%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Nov 25, 2025 · EUVD

    Detected

    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.

  2. Jan 20, 2026 · EUVD

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2025-66019

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-66019

    30-day exploitation probability 0.39%

    first.org
  • EUVDVulnerability recordEUVD-2025-199017

    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 iss

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Nov 5, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 5, 2026
  • CVE.orgOct 27, 2026
  • EUVDOct 27, 2026