by Kastro CVE-2025-25200
koajs koa — Koa has Inefficient Regular Expression Complexity
Description · from the CVE record
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.
Affected
ProductAffectedFixed inSource
koa< 0.21.2–CNA
koa>= 1.0.0, < 1.7.1–CNA
koa>= 2.0.0-alpha.1, < 2.15.4–CNA
koa>= 3.0.0-alpha.0, < < 3.0.0-alpha.3–CNA
Scores by source
GitHub_M (CNA)9.2CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: partial