CVE-2025-25200
Koa is expressive middleware for Node.js using ES2017 async functions. Prior to versions 0.21.2, 1.7.1, 2.15.4, and 3.0.0-alpha.3, Koa uses an evil regex to parse the `X-Forwarded-Proto` and `X-Forwarded-Host` HTTP headers. This can be exploited to carry out a Denial-of-Service attack. Versions 0.21.2, 1.7.1, 2.15.4, and 3.0.0-alpha.3 fix the issue.
Scoring
- Severity
- CRITICAL
- CVSS base score
- 9.2
- CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
- EPSS probability
- 0.84%
- CWE
- CWE-1333
- Published
- 2025-02-12
- Last modified
- 2026-03-12
Affected products
- koajs koa
- koajs koa
- koajs koa
- koajs koa
Weakness type
Related vulnerabilities
- CVE-2026-75880 — Apache Artemis, Apache ActiveMQ Artemis: Message selector wildcard handling could lead to denial of service
- CVE-2026-87819 — GitPython before 3.1.60 Denial of Service via ReDoS
- CVE-2026-86081 — n8n: Regular Expression Denial of Service in the Default Blocked-File-Pattern Match via a Git Node Clone Path
- CVE-2026-85062 — Colord: Slow rejection of oversized malformed color strings
- CVE-2026-83619 — xmldom: End-tag Whitespace-Trim Regex ReDoS — quadratic backtracking in the 0.8.x end-tag parser
- CVE-2026-83606 — xmldom PI grammar regex ReDoS: quadratic backtracking on unterminated processing instructions
- CVE-2024-58379 — nodemailer before 6.9.9 ReDoS via attachDataUrls parameter
- CVE-2026-55520 — Protego: Exponential backtracking ReDoS in robots.txt URL wildcard matching