CVE-2026-115348
Description
A flaw was found in mistune. A remote, unauthenticated attacker can exploit an algorithmic complexity vulnerability in the inline link parser by submitting specially crafted Markdown input containing numerous unbalanced brackets. This forces repeated forward scans during text parsing, consuming excessive CPU resources and resulting in a Denial of Service (DoS).
Statement
Red Hat rates this flaw as having an Important severity because unauthenticated network actors can cause severe CPU saturation in services parsing untrusted Markdown content, rendering backend worker processes unresponsive. The impact directly threatens multi-tenant web applications, data science workbenches, and pipeline runtime environments that accept external documents for parsing. In architectures where access is strictly confined to authenticated, trusted users or where input document sizes and processing timeouts are enforced, the practical operational risk is substantially minimized.
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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