GitHub Advisoryadvisory · PyPI
GHSA-wgvp-vg3v-2xq3 pypdf has possible long runtimes/large memory usage for large /ToUnicode streams
MEDIUM
Official page ↗
- Aliases
- CVE-2026-27025
- Ecosystem
- PyPI
- Packages
- pypdf
- Severity
- Moderate
- CVSS vector
- CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- Weaknesses
- CWE-834
- Reviewed
- 2026-02-18
Affected packages
• PyPI pypdf: < 6.7.1 → fixed in 6.7.1
Description
Impact
An attacker who uses this vulnerability can craft a PDF which leads to long runtimes and large memory consumption. This requires parsing the `/ToUnicode` entry of a font with unusually large values, for example during text extraction.
Patches
This has been fixed in pypdf==6.7.1.
Workarounds
If you cannot upgrade yet, consider applying the changes from PR #3646.
Related
Alias · CVE (1)
- CVE-2026-27025 pypdf is a free and open-source pure-python PDF library. vulnerability
Weakness · CWE (1)
- CWE-834 Excessive Iteration weakness
References
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-wgvp-vg3v-2xq3 web
- https://nvd.nist.gov/vuln/detail/CVE-2026-27025 advisory
- https://github.com/py-pdf/pypdf/pull/3646 web
- https://github.com/py-pdf/pypdf/commit/77d7b8d7cfbe8dd179858dfa42666f73fc6e57a2 web
- https://github.com/py-pdf/pypdf package
- https://github.com/py-pdf/pypdf/releases/tag/6.7.1 web