critical9.2
CVE-2025-25200
Inefficient Regular Expression Complexity in koa
Impact
### Summary 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. ### PoC Coming soon. ### Impact This is a Regex Denial-of-Service attack and causes memory exhaustion. The regex should be improved and empty values should not be allowed.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | koa | >= 2.0.0, < 2.15.4 | 2.15.4 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Koajs | Koa | before 0.21.2 from 1.0.0 before 1.7.1 from 2.0.0 before 2.15.4 Version 3.0.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- 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/commit/5054af6e31ffd451a4151a1fe144cef6e5d0d83c
- https://github.com/koajs/koa/commit/5f294bb1c7c8d9c61904378d250439a321bffd32
- https://github.com/koajs/koa/commit/93fe903fc966635a991bcf890cfc3427d33a1a08
- https://github.com/koajs/koa/releases/tag/2.15.4
- https://github.com/koajs/koa/security/advisories/GHSA-593f-38f6-jp5m
- https://github.com/advisories/GHSA-593f-38f6-jp5m
- https://nvd.nist.gov/vuln/detail/CVE-2025-25200