CVE-2026-76098
Description
A flaw was found in Mistune, a Python Markdown parser. This vulnerability allows a remote attacker to trigger a Denial of Service (DoS) by submitting specially crafted Markdown input. The excessive use of emphasis markers, such as consecutive asterisks, creates deeply nested tokens during HTML rendering. This process can exceed Python's recursion limit, causing the parsing application to crash.
Statement
This flaw in the Mistune Python Markdown parser can lead to a denial of service in Red Hat OpenShift AI and Migration Toolkit for Applications. By submitting specially crafted Markdown input with excessive emphasis markers, an attacker can trigger deep recursion, causing the parsing process to crash and disrupt service availability.
Mitigation
Mitigation for this issue involves restricting the processing of untrusted Markdown content by applications utilizing the vulnerable Mistune library. If applications are exposed to untrusted input, implement input sanitization to prevent deeply nested emphasis structures that could trigger the denial of service.
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); 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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