What is CVE-2026-55603?

CVE-2026-55603 is a high-severity vulnerability in Chimurai Http-proxy-middleware, classified under CRLF Injection. CVSS score: 7.5/10. Published 2026-06-22.

How severe is CVE-2026-55603?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Chimurai Http-proxy-middleware

CVE-2026-55603

http-proxy-middleware is node.js http-proxy middleware. From 3.0.4 until 3.0.7 and 4.1.1, fixRequestBody() is the library's documented helper for re-emitting a request body that was already consumed by a body parser. When the outgoing Cont…

Vulnerability class: CRLF Injection

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N.

Affected products

Chimurai Http-proxy-middleware — versions >= 3.0.4, < 3.0.7, >= 4.0.0, < 4.1.1

Weakness classification (CWE)

CWE-93 — CRLF Injection

References

security-advisories@github.com (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2026-55603?: CVE-2026-55603 is a high-severity vulnerability in Chimurai Http-proxy-middleware, classified under CRLF Injection. CVSS score: 7.5/10. Published 2026-06-22.
How severe is CVE-2026-55603?: High severity. CVSS v3 base score is 7.5 out of 10.