CVE-2026-55603
Description
A flaw was found in http-proxy-middleware. A remote attacker could exploit a vulnerability in the fixRequestBody() function, which is used to re-emit a request body. By injecting carriage return and line feed characters (\r\n) into a request body key or value, an attacker can bypass security policies and validation performed by the proxy. This desynchronization between the proxy and the backend server can lead to a compromise of data integrity.
Statement
Red Hat rates this issue as having Moderate impact for Red Hat products that bundle http-proxy-middleware 3.0.5 in a proxy configuration that re-emits an already-consumed request body via fixRequestBody(). Affected components are tracked via delegated engineering trackers and include Cluster Observability Operator's Prometheus console proxy, the Konflux mintmaker-renovate-image, Migration Toolkit for Applications (MTA) UI, RHTAS console UI, and RHTPA/Trustification service. Red Hat OpenShift AI MLflow images were initially assessed as in-scope but ship http-proxy-middleware 1.3.1/2.0.6, both outside the vulnerable ranges (>= 3.0.4, < 3.0.7 and >= 4.0.0, < 4.1.1), and are not affected. Other Red Hat products either do not bundle an affected http-proxy-middleware version or do not expose the vulnerable code path in normal operation.
Mitigation
Restrict network access to affected proxy services. Do not pass untrusted user input into proxy target or header configuration. Upgrade http-proxy-middleware to 3.0.7 or 4.1.1 (or later) once updated packages are available for the affected components.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Changed | N/A | Changed |
| Confidentiality | Low | N/A | Low |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Application Data
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