CVE-2019-25781
Description
A flaw was found in Python-Markdown. An algorithmic complexity vulnerability in inline link parsing allows a remote attacker to cause a Denial of Service (DoS) by exhausting CPU resources. By submitting specially crafted Markdown text containing repeated unmatched brackets, an attacker can force the parser into inefficient scanning loops that consume excessive CPU time and stall worker processes.
Statement
This vulnerability is rated as Important because an unauthenticated remote attacker can cause severe service degradation and worker thread exhaustion by submitting minimal payloads with unmatched bracket syntax. Across Red Hat environments, the python-markdown library is integrated into various backend platforms, including Red Hat Ansible Automation Platform, Red Hat Satellite, and OpenShift AI, where it processes formatted text and template data. Systems that expose Markdown rendering endpoints directly to untrusted network traffic are at high risk of denial of service. The impact is substantially lower in deployments where rendering is restricted to verified administrators or internal sources.
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 | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU)
Frequently Asked Questions
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