Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-08-07T19:28:26 pypdf: pypdf: Denial of Service via crafted PDF with large /ToUnicode streams 5.5 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H CWE-770

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.

A flaw was found in pypdf, a pure-python PDF library. A remote attacker could exploit this vulnerability by providing a specially crafted PDF file. When the library attempts to parse unusually large font /ToUnicode CMap streams during text extraction, it can lead to excessive memory consumption. This can result in a denial of service (DoS) for applications processing such malicious PDF files.

A flaw in the pypdf library can lead to a denial of service due to uncontrolled resource consumption. Processing a specially crafted PDF file containing unusually large /ToUnicode streams can cause excessive memory allocation, impacting the availability of Red Hat products that rely on pypdf for PDF processing. This issue requires user interaction to trigger the vulnerable parsing. To reduce exposure, avoid processing untrusted PDF files with applications that use the pypdf library. If processing untrusted content is necessary, deploy affected applications within a sandboxed environment to contain potential resource exhaustion. Exploit Intelligence Out of support scope exploit-intelligence-tech-preview/vulnerability-analysis-rhel9 Lightspeed Core Fix deferred lightspeed-core/lightspeed-stack-rhel9 Lightspeed Core Fix deferred lightspeed-core/rag-tool-cpu-rhel9 Lightspeed Core Fix deferred lightspeed-core/rag-tool-cuda-12.9-rhel9 OpenShift Lightspeed Fix deferred openshift-lightspeed/lightspeed-ocp-rag-rhel9 OpenShift Lightspeed Fix deferred openshift-lightspeed-tech-preview/lightspeed-rag-tool-rhel9 Red Hat Ansible Automation Platform 2 Out of support scope ansible-automation-platform-25/lightspeed-chatbot-rhel8 Red Hat Enterprise Linux AI (RHEL AI) 3 Fix deferred rhelai3/bootc-cuda-rhel9 Red Hat Enterprise Linux AI (RHEL AI) 3 Fix deferred rhelai3/bootc-gaudi-rhel9 Red Hat Enterprise Linux AI (RHEL AI) 3 Fix deferred rhelai3/bootc-rocm-rhel9 Red Hat Enterprise Linux AI (RHEL AI) 3 Fix deferred rhelai3/disk-image-cuda-rhel9 Red Hat OpenShift AI (RHOAI) Fix deferred rhoai/odh-llama-stack-core-rhel9 Red Hat Quay 3 Out of support scope quay/quay-rhel8 Red Hat Quay 3 Fix deferred quay/quay-rhel9 https://www.cve.org/CVERecord?id=CVE-2026-71870 https://nvd.nist.gov/vuln/detail/CVE-2026-71870 https://github.com/py-pdf/pypdf/commit/afba8080e19d29a3c256a742b340995e695b35aa https://github.com/py-pdf/pypdf/pull/3944 https://github.com/py-pdf/pypdf/releases/tag/6.15.0 https://github.com/py-pdf/pypdf/security/advisories/GHSA-fp3f-mc75-235c