PyPDF's Manipulated FlateDecode streams can exhaust RAM
### Impact An attacker who uses this vulnerability can craft a PDF which leads to the RAM being exhausted. This requires just reading the file if a series of FlateDecode filters is used on a malicious cross-reference stream. Other content streams are affected on explicit access. ### Patches This has been fixed in [pypdf==6.0.0](https://github.com/py-pdf/pypdf/releases/tag/6.0.0). ### Workarounds If you cannot upgrade yet, you might want to implement the workaround for `pypdf.filters.decompress` yourself: https://github.com/py-pdf/pypdf/blob/0dd57738bbdcdb63f0fb43d8a6b3d222b6946595/pypdf/filters.py#L72-L143 ### References This issue has been reported in #3429 and fixed in #3430.
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2025-55197US | high7.5 | — | ||
pypdf is a free and open-source pure-python PDF library. Prior to version 6.0.0, an attacker can craft a PDF which leads to the RAM being exhausted. This requires just reading the… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/advisories/GHSA-7hfw-26vp-jp8mADVISORY
- https://github.com/py-pdf/pypdfPACKAGE
- https://github.com/py-pdf/pypdf/blob/0dd57738bbdcdb63f0fb43d8a6b3d222b6946595/pypdf/filters.py#L72-L143WEB
- https://github.com/py-pdf/pypdf/issues/3429WEB
- https://github.com/py-pdf/pypdf/pull/3430WEB
- https://github.com/py-pdf/pypdf/releases/tag/6.0.0WEB
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-7hfw-26vp-jp8mWEB
- https://nvd.nist.gov/vuln/detail/CVE-2025-55197ADVISORY
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