CVE-2021-22903

MEDIUM
6.1
CVSS Score
Published: June 11, 2021 at 03:49 PM UTC
Updated: June 17, 2026 at 03:37 AM UTC
1 product affected across 1 vendorRails

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Severity
MEDIUM6.1
Exploit prediction
EPSS 1%

Description

The actionpack ruby gem before 6.1.3.2 suffers from a possible open redirect vulnerability. Specially crafted Host headers in combination with certain "allowed host" formats can cause the Host Authorization middleware in Action Pack to redirect users to a malicious website. This is similar to CVE-2021-22881. Strings in config.hosts that do not have a leading dot are converted to regular expressions without proper escaping. This causes, for example, `config.hosts << "sub.example.com"` to permit a request with a Host header value of `sub-example.com`.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.1.1 ≤ v < 6.1.3.26.1.0 rc2
Vendor states this is fixed in 6.1.3.2 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-601

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