CVE-2026-115352
Description
A flaw was found in mistune. This algorithmic complexity vulnerability allows an unauthenticated remote attacker to cause a Denial of Service (DoS) by submitting specially crafted Markdown input containing long sequences of unmatched bracket characters. When parsing this malformed input, the inline link parser consumes excessive CPU resources, rendering processing workers unresponsive.
Statement
This vulnerability is rated as Important because remote, unauthenticated attackers can cause severe denial of service through algorithmic complexity without requiring elevated privileges or interaction. In Red Hat environments such as OpenShift and OpenShift AI, services that render untrusted Markdown content using python-mistune can experience substantial CPU exhaustion, causing worker processes to become unresponsive. The security risk is limited to service availability, with no breach of system integrity or data confidentiality.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
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
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