Regular expression denial of service in markdown-it
Priority HIGH 70CWE-1333Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-1333.
Summary
Versions of the package markdown-it from 13.0.0 and before 14.1.1 are vulnerable to Regular Expression Denial of Service (ReDoS) due to the use of the regex /\*+$/ in the linkify function. An attacker can supply a long sequence of * characters followed by a non-matching character, which triggers excessive backtracking and may lead to a denial-of-service condition.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00739 54th percentileScored 2026-11-07
Fix Fixed markdown-it: 14.1.1markdown-it (npm): 14.1.1Red Hat: 1 advisory
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | markdown-it | 13.0.0 to before 14.1.1 | 14.1.1 | Patch available | CNA |
| — | markdown-it (npm) | 13.0.0 to before 14.1.1 | 14.1.1 | Patch available | GHSA-38c4-r59v-3vqw |
- markdown-it Vendor— Affected 13.0.0 to before 14.1.1 Fixed in 14.1.1 Patch available CNA
- markdown-it (npm) Vendor— Affected 13.0.0 to before 14.1.1 Fixed in 14.1.1 Patch available GHSA-38c4-r59v-3vqw
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:markdown-it_project:markdown-it:*:*:*:*:*:*:*:* | 13.0.0 to before 14.1.1 | Vulnerable | Markdown-it Project |
- cpe:2.3:a:markdown-it_project:markdown-it:*:*:*:*:*:*:*:* Versions 13.0.0 to before 14.1.1 Vulnerable ·Markdown-it Project
Remediation
- Fix · CNA markdown-it Fixed in 14.1.1
- Fix · GHSA-38c4-r59v-3vqw markdown-it (npm) Fixed in 14.1.1 Advisory →
Red Hat 1 advisory
- RHSA-2026:21772 Released 2026-05-28 · Red Hat rating ImportantRed Hat OpenShift Dev Spaces 3.28.0 Release.
- Red Hat OpenShift Dev Spaces 3.28 registry.redhat.io/devspaces/code-rhel9, registry.redhat.io/devspaces/dashboard-rhel9, registry.redhat.io/devspaces/openvsx-rhel9 +3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat OpenShift Dev Spaces 3.28 | Fixed | RHSA-2026:21772 |
Not affected: 5 products
- Logging Subsystem for Red Hat OpenShift
- Red Hat Developer Hub 1
- Red Hat OpenShift Dev Spaces
- Red Hat OpenShift Dev Spaces 3.28
- Self-service automation portal 2
Timeline
- 2026-10-02 Threatist record created from CVE-2026-2327
- 2026-10-03 Alias added: GHSA-38c4-r59v-3vqw
- 2026-10-27 Affected versions changed · Red Hat
References
Advisory 2
More Markdown-it Project Markdown-it vulnerabilities
- TI-2025-07289 Markdown-it 14.1.0 - Cross-site scripting (XSS) CVSS 4.0MEDIUM 6.9
- TI-2026-36244 markdown-it: Quadratic complexity DoS in smartquotes rule via replaceAt string operations CVSS 3.1MEDIUM 5.3
- TI-2022-06047 Uncontrolled Resource Consumption in markdown-it CVSS 3.1MEDIUM 5.3
- TI-2015-07933 markdown-it html_re.js redos CVSS 3.1HIGH 7.5
- TI-2015-02915 markdown-it before 4.1.0 does not block data: URLs. CVSS 3.0MEDIUM 5.3
Sources
- CVE-2026-2327 · CVE Program
- CVE-2026-2327 · NVD
- FIRST EPSS
- GHSA-38c4-r59v-3vqw · GitHub Advisory Database · CC BY 4.0
- CVE-2026-2327 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences