CVE-2026-115347 Details
Description
Mistune before 3.3.0 contains an inefficient algorithmic complexity vulnerability in parse_link_text that allows remote attackers to cause denial of service through unbalanced square brackets. Attackers can submit markdown containing long runs of unmatched brackets to mistune.html(), triggering repeated forward scans that stall worker processes for minutes.
A denial-of-service vulnerability has been identified in Mistune versions prior to 3.3.0. The issue arises from an inefficient algorithmic complexity in the 'parse_link_text' function, where remote attackers can cause service degradation by sending markdown with long sequences of unmatched square brackets. This manipulation leads to unbalanced bracket parsing, causing the 'mistune.html()' function to perform repeated forward scans that can freeze worker processes for several minutes.
Users are advised to update Mistune to version 3.3.0 or later.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Oct 22, 2026CISA-ADP
Assessed Oct 26, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/lepture/mistune/security/advisories/GHSA-f32h-38gf-rg5r | [email protected] | AdvisoryExploitRemedyVendor |
| https://www.vulncheck.com/advisories/mistune-before-3.3.0-quadratic-denial-of-service-via-parse-link-text | [email protected] | AdvisoryBroken Link |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-407 | Inefficient Algorithmic Complexity | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| Mistune | 3.2.0 (semver) 3.2.1 (semver) main |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Oct 26, 2026 | CVE Modified | CISA-ADP |
| Oct 22, 2026 | New CVE Received | [email protected] |