Vulnerability · Published Oct 28, 2026 · Assigned by VulnCheck
CVE-2026-118694python-markdown2 through 2.5.5 Denial of Service via Unclosed Inline Link Destinations
High 7.5
In plain English
A high-severity security flaw in python-markdown2 from trentm. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities).
Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.5%top 60.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
python-markdown2 through 2.5.5 contains a denial of service vulnerability that allows remote users to exhaust CPU by submitting Markdown with unclosed inline link destinations. Attackers can submit repeated '[a](' or '
| Vendor | Product | Versions |
|---|---|---|
| trentm | python-markdown2 | 0 – through 2.5.5 |
Weakness: CWE-407 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- GitHub Issue #750 issue-tracking
- https://github.com/trentm/python-markdown2 product
- https://github.com/trentm/python-markdown2/blob/2.5.5/lib/markdown2.py#L1478-L1492 technical-description
- https://github.com/trentm/python-markdown2/blob/2.5.5/lib/markdown2.py#L3029 technical-description
- https://github.com/trentm/python-markdown2/pull/751 patch, issue-tracking
- VulnCheck Advisory: python-markdown2 through 2.5.5 Denial of Service via Unclosed Inline Link Destinations third-party-advisory