Is CVE-2026-27026 actively exploited?

CVE-2026-27026 has no public evidence of in-the-wild exploitation as of 2026-02-24.

What is the CVSS score for CVE-2026-27026?

CVE-2026-27026 has a CVSS score of 6.9 (MEDIUM severity). 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X.

How do I patch CVE-2026-27026?

Patch guidance is available from pypdf project security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2026-27026.

Which products are affected by CVE-2026-27026?

1 product: pypdf project pypdf.

CVE-2026-27026 - remediation guidance & executive summary

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.7.1, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a malformed /FlateDecode stream, where the byte-by-byte decompression is used. This vulnerability is fixed in 6.7.1.

CVSS Metrics

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector: local
Complexity: low
Privileges: none
User Action: none
Confidentiality: undefined
Integrity: undefined
Availability: undefined
Weaknesses: CWE-770

Metadata

Primary Vendor: PYPDF_PROJECT
Published: 2/20/2026
Last Modified: 2/24/2026
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

CVE-2026-27026

Description

CVSS Metrics

Metadata

Affected Products

Remediation Guidance

Executive Summary