CVE-2026-102995

pypdf: Possible large memory usage for large /ToUnicode streams (Follow-up 2)

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF can place unusually large source-code or destination-string tokens in a font /ToUnicode mapping, causing pypdf/_cmap.py parse_bfchar to decode and retain oversized values during operations such as text extraction and consume excessive memory. This is a second follow-up to earlier /ToUnicode resource-consumption fixes and is limited to the remaining token-length path. This issue is fixed in version 6.18.1.

Scores

Weaknesses (CWE)

• CWE-400

Advisories

• GHSA-fp3h-c4fm-7vvf — pypdf: Possible large memory usage for large /ToUnicode streams (Follow-up 2)
• PYSEC-2026-4154 — pypdf: Possible large memory usage for large /ToUnicode streams (Follow-up 2)

European references

• ENISA EUVD · EUVD-2026-90367
• GCVE · GCVE-0-2026-102995

Affected configurations (NVD CPE)

• cpe:2.3:a:pypdf_project:pypdf:*:*:*:*:*:*:*:* < 6.18.1

Affected products

References

• https://github.com/py-pdf/pypdf/security/advisories/GHSA-fp3h-c4fm-7vvf
• https://github.com/py-pdf/pypdf/pull/4071
• https://github.com/py-pdf/pypdf/commit/319d0b823ce2c311a2435e9fd93c13994d32bb51
• https://github.com/py-pdf/pypdf/releases/tag/6.18.1

Sources