CVE-2026-48156

pypdf: Possible long runtimes for zero-only width values in cross-reference streams

Published May 28, 2026 CVSS 4.0 · 5.1 Medium EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-248m-82v9-q6g6 pypdf: Possible long runtimes for zero-only width values in cross-reference streamsuntimes for zero-only width values in cross-reference streams
History
Type Values Removed Values Added
CPEs cpe:2.3:a:pypdf_project:pypdf:*:*:*:*:*:*:*:* cpe:2.3:a:py-pdf:pypdf:*:*:*:*:*:*:*:*
Vendors & Products Pypdf Project
Pypdf Project pypdf
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Pypdf Project
Pypdf Project pypdf
CPEs cpe:2.3:a:pypdf_project:pypdf:*:*:*:*:*:*:*:*
Vendors & Products Pypdf Project
Pypdf Project pypdf
Metrics cvssV3_1

{'score': 3.3, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L'}

Type Values Removed Values Added
First Time appeared Py-pdf
Py-pdf pypdf
Vendors & Products Py-pdf
Py-pdf pypdf
Type Values Removed Values Added
Description 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.
Title pypdf: Possible long runtimes for zero-only width values in cross-reference streams
Weaknesses CWE-834
References
Metrics cvssV4_0

{'score': 5.1, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 30, 2026, 2:08 AM
Reserved
May 20, 2026, 11:12 PM
Status
Analyzed
Published
May 28, 2026, 4:16 PM
Modified
Nov 2, 2026, 4:06 PM
Severity
Low
Public date
May 28, 2026, 2:50 PM