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Vulnerability · Published Aug 7, 2026 · Assigned by GitHub_M

CVE-2026-71870pypdf: Possible large memory usage for large /ToUnicode streams

Medium 4.8

In plain English

A medium-severity uncontrolled resource consumption in pypdf from py-pdf. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)4.8Medium
Exploit odds (30 days)0.1%top 97.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, a crafted PDF can cause large memory consumption when pypdf/_cmap.py function parse_bfrange parses unusually large source-code or destination-string tokens in a font /ToUnicode CMap during text extraction. This issue is fixed in 6.15.0.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12pypdfno fix listedDEBIAN-CVE-2026-71870
Debian:13pypdfno fix listedDEBIAN-CVE-2026-71870
Debian:14pypdf6.19.0-1DEBIAN-CVE-2026-71870
Debian:12pypdf2no fix listedDEBIAN-CVE-2026-71870
PyPIpypdf6.15.0PYSEC-2026-3655
PyPIpypdf6.15.0GHSA-fp3f-mc75-235c
Ubuntu:24.04:LTSpypdfno fix listedUBUNTU-CVE-2026-71870
Ubuntu:26.04:LTSpypdfno fix listedUBUNTU-CVE-2026-71870
Ubuntu:26.10pypdfno fix listedUBUNTU-CVE-2026-71870

Affected products (as reported)

VendorProductVersions
py-pdf pypdf < 6.15.0

Weakness: CWE-400 · Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

References