CVE-2026-54651
Description
A flaw was found in pypdf. An attacker can craft a malicious PDF file that, when merged with threads or articles into a writer, can lead to an an infinite loop. This vulnerability can result in a Denial of Service (DoS) condition, making the affected system unresponsive.
Statement
Red Hat rates this issue as Moderate severity (CVSS 5.9) because exploitation requires a specially crafted PDF containing thread/article objects to be processed by pypdf's merge functionality.
Mitigation
If PDF processing is required, implement processing timeouts and resource constraints (CPU/memory limits) to contain the impact of infinite loops. Running pypdf workloads in containerized processes with enforced resource limits provides defense-in-depth.
Upgrading to pypdf >= 6.13.1 resolves this issue.
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 | 5.9 | 5.5 | N/A |
| Attack Vector | Network | Local | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | None | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Amplification
An infinite loop will cause unexpected consumption of resources, such as CPU cycles or memory. The software's operation may slow down, or cause a long time to respond.
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