pypdf: Possible large memory usage for large /ToUnicode streams
### 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==6.15.0](https://github.com/py-pdf/pypdf/releases/tag/6.15.0). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#3944](https://github.com/py-pdf/pypdf/pull/3944).
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describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-71870US | low3.3 | — | ||
pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, a crafted PDF can cause large memory consumption when pypdf/_cmap.py function parse_bfrange parses unusual… | ||||
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references
External citations — patches, advisories, analysis.
- https://github.com/advisories/GHSA-fp3f-mc75-235cADVISORY
- https://github.com/py-pdf/pypdfPACKAGE
- https://github.com/py-pdf/pypdf/commit/afba8080e19d29a3c256a742b340995e695b35aaWEB
- https://github.com/py-pdf/pypdf/pull/3944WEB
- https://github.com/py-pdf/pypdf/releases/tag/6.15.0WEB
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-fp3f-mc75-235cWEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-71870ADVISORY
- https://pypi.org/project/pypdfPACKAGE
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