pypdf is a free and open-source pure-python PDF library.

Code

The project this record applies to. Exploit listings stay in References.

• Repository · github.com

Timeline

Detection, updates, and resolution for this record.

1. May 28, 2026 · NIST NVD

   Detected

   pypdf is a free and open-source pure-python PDF library. Prior to 6.12.0, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires cross-reference streams with /W [0 0 0] values and large /Size values. This vulnerability is fixed in 6.12.0.

2. Oct 14, 2026 · NIST NVD

   Updated

   pypdf is a free and open-source pure-python PDF library. Prior to 6.12.0, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires cross-reference streams with /W [0 0 0] values and large /Size values. This vulnerability is fixed in 6.12.0.

Affected

• cpe pypdf project/pypdfversion unspecified

Sources

• CVE.orgVulnerability recordCVE-2026-48156

  Official CVE identifier

  cve.org
• FIRST EPSSExploitation probabilityCVE-2026-48156

  30-day exploitation probability 0.2%

  first.org
• NIST NVDVulnerability recordCVE-2026-48156

  pypdf is a free and open-source pure-python PDF library. Prior to 6.12.0, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires cross-reference streams with /W [0 0 0] values and large /Size values. This vulnerability is fixed in 6.12

  nvd.nist.gov

References

• Issue Tracking · github.com
• Release Notes · github.com
• Patch · github.com