Modular Ruby Web Server Interface Vulnerability in Rack by Rack
CVE-2026-32762

4.8MEDIUM

Key Information:

Vendor

Rack

Status
Rack
Vendor
CVE Published:
2 April 2026

What is CVE-2026-32762?

The Rack framework for Ruby, particularly versions prior to 3.1.21 and 3.2.6, has been discovered to improperly handle the RFC 7239 Forwarded header. This improper parsing can lead to a scenario where attackers exploit mismanaged quoted-string values. In environments where an upstream proxy or WAF handles these headers differently, it becomes possible to smuggle malicious parameters, leading to possible security breaches.

Affected Version(s)

rack >= 3.0.0.beta1, < 3.1.21 < 3.0.0.beta1, 3.1.21

rack >= 3.2.0, < 3.2.6 < 3.2.0, 3.2.6

References

https://github.com/rack/rack/security/advisories/GHSA-qfg...
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CVSS V3.1

Score:
4.8
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.