pypdf: Possible large memory usage for large /ToUnicode streams (Follow-up 2)
### Impact An attacker who uses this vulnerability can craft a PDF which leads to 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==6.18.1](https://github.com/py-pdf/pypdf/releases/tag/6.18.1). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#4071](https://github.com/py-pdf/pypdf/pull/4071).
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-102995US | high7.5 | — | ||
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 mapp… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/py-pdf/pypdfPACKAGE
- https://github.com/py-pdf/pypdf/commit/319d0b823ce2c311a2435e9fd93c13994d32bb51WEB
- https://github.com/py-pdf/pypdf/pull/4071WEB
- https://github.com/py-pdf/pypdf/releases/tag/6.18.1WEB
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-fp3h-c4fm-7vvfWEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-102995ADVISORY
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