CVE-2025-25200: koa — Fix

Description

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.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-1333 CWE-1333

Affected Products

Vendor	Product	Versions
koajs	koa	< 0.21.2
koajs	koa	1.0.0 — 1.7.1
koajs	koa	2.0.0 — 2.15.4
koajs	koa	All
koajs	koa	All
koajs	koa	All

References

Advisories & Patches

https://github.com/koajs/koa/commit/5054af6e31ffd451a4151a1fe144cef6e5d0d83c https://github.com/koajs/koa/commit/5f294bb1c7c8d9c61904378d250439a321bffd32 https://github.com/koajs/koa/commit/93fe903fc966635a991bcf890cfc3427d33a1a08 https://github.com/koajs/koa/security/advisories/GHSA-593f-38f6-jp5m

Other References

https://github.com/koajs/koa/blob/master/lib/request.js#L259 https://github.com/koajs/koa/blob/master/lib/request.js#L404 https://github.com/koajs/koa/releases/tag/2.15.4

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2025-25200? +

CVE-2025-25200 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-25200? +

CVE-2025-25200 affects products from koajs, specifically: koa. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-25200? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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