pypdf: Unvalidated JPEG image data loading
### Impact An attacker who uses this vulnerability can craft a PDF which leads to arbitrary image parsers being called. This requires loading an image which claims to use the `/DCTDecode` filter (JPEG data). Users which do not have the optional *Pillow* dependency installed in their environment are not affected. ### Patches This has been fixed in [pypdf==6.21.1](https://github.com/py-pdf/pypdf/releases/tag/6.21.1). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#4222](https://github.com/py-pdf/pypdf/pull/4222).
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-113786US | — | — | ||
pypdf is a free and open-source pure-python PDF library. Prior to 6.21.1, an attacker can craft a PDF containing image data labeled with the /DCTDecode filter that causes Pillow to… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/py-pdf/pypdfPACKAGE
- https://github.com/py-pdf/pypdf/commit/512d8eb94eb04be1d1c90504e6da2dcef8679e07WEB
- https://github.com/py-pdf/pypdf/pull/4222WEB
- https://github.com/py-pdf/pypdf/releases/tag/6.21.1WEB
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-5hx5-vpf9-5wcvWEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-113786ADVISORY
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