CVE-2026-71870
Description
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.
Statement
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.
Mitigation
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.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | Required | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
When allocating resources without limits, an attacker could prevent other systems, applications, or processes from accessing the same type of resource. It can be easy for an attacker to consume many resources by rapidly making many requests or causing larger resources to be used than is needed.
Frequently Asked Questions
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