High severity · published Feb 12, 2025
CVE-2025-25200
Koa has Inefficient Regular Expression Complexity
7.5
CVSS
0.8%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.8% · higher than 58% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KO
koa · koajs
< 0.21.2; >= 1.0.0, < 1.7.1; >= 2.0.0-alpha.1, < 2.15.4; >= 3.0.0-alpha.0, < < 3.0.0-alpha.3 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-25200
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-25200
Product
https://github.com/koajs/koa/blob/master/lib/request.js#L259
Product
https://github.com/koajs/koa/blob/master/lib/request.js#L404
Patch
https://github.com/koajs/koa/commit/5054af6e31ffd451a4151a1fe144cef6e5d0d83c
Patch
https://github.com/koajs/koa/commit/5f294bb1c7c8d9c61904378d250439a321bffd32
Patch
https://github.com/koajs/koa/commit/93fe903fc966635a991bcf890cfc3427d33a1a08
Release Notes
https://github.com/koajs/koa/releases/tag/2.15.4
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