pypdf: Missing stream length values ignore defined limits
Impact
An attacker who uses this vulnerability can craft a PDF which leads to large memory usage, as MAX_DECLARED_STREAM_LENGTH is sometimes ignored. This requires parsing a content stream without a /Length value.
Patches
This has been fixed in pypdf==6.13.3.
Workarounds
If you cannot upgrade yet, consider applying the changes from PR #3871.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | pypdf | < 6.13.3 | 6.13.3 |
References
- CVSS vector
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N- Weakness (CWE)
CWE-400, CWE-770- Platform
- Python (PyPI)
- Package
pypdf- Disclosed
- 18.06.2026
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - GHSA-jm82-fx9c-mx94 - CC BY 4.0
Vulnerability history: pypdf
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 51
- First → latest
- 06.2023 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 10
- Medium 38
- Low 3
Disclosures per year
- 2023: 2
- 2024: 0
- 2025: 4
- 2026: 45
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pypdf: Missing stream length values ignore defined limits this entry
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