Vulnerability in Koajs Koa
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 exp…
Vulnerability class: ReDoS (Regular Expression Denial of Service)
EPSS: 0.008 (51.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Koajs Koa — versions >= 2.0.0-alpha.1, < 2.15.4, >= 1.0.0, < 1.7.1, < 0.21.2
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Product, x_refsource_MISC)
- security-advisories@github.com (Product, x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2025-25200?
- CVE-2025-25200 is a high-severity vulnerability in Koajs Koa, classified under Inefficient Regular Expression Complexity. CVSS score: 7.5/10. Published 2025-02-12.
- How severe is CVE-2025-25200?
- High severity. CVSS v3 base score is 7.5 out of 10.
- Is CVE-2025-25200 known to be exploited?
- 5 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.