CVE-2026-118656
Description
A flaw was found in Echo. This vulnerability allows an open redirect to an untrusted domain due to improper validation of redirect targets during Uniform Resource Identifier (URI) sanitization. When trailing slash redirect middleware is configured, a specially crafted path containing tab characters can bypass validation checks. A remote attacker can exploit this flaw by enticing a user to visit a malicious link, redirecting them to an arbitrary external website to facilitate phishing attacks.
Statement
This vulnerability is rated as having Moderate severity because exploitation requires user interaction to follow an attacker-supplied link and is contingent on non-default middleware configurations. Within Red Hat environments, applications utilizing the Echo framework are only exposed if the trailing slash middleware is explicitly configured with an HTTP redirect status. In default configurations, the middleware performs internal URL rewrites instead of issuing external redirects, mitigating unauthenticated redirection risks.
Understanding the Weakness (CWE)
Access Control
Technical Impact: Bypass Protection Mechanism; Gain Privileges or Assume Identity
The user may be redirected to an untrusted page that contains malware which may then compromise the user's system. In some cases, an open redirect can also enable the immediate download of a file without the user's permission, because the redirection to an external site may lead to endpoints on those sites that automatically trigger a download action ("drive-by download" [REF-1478]). This will expose the user to extensive risk. The user's interaction with the web server may also be compromised if the malware conducts keylogging or other attacks that steal credentials, personally identifiable information (PII), or other important data.
Access Control,Confidentiality,Other
Technical Impact: Bypass Protection Mechanism; Gain Privileges or Assume Identity; Other
By modifying the URL value to a malicious site, an attacker may successfully launch a phishing scam. The user may be subjected to phishing attacks by being redirected to an untrusted page. The phishing attack may point to an attacker controlled web page that appears to be a trusted web site. The phishers may then steal the user's credentials and then use these credentials to access the legitimate web site. Because the server name in the modified link is identical to the original site, phishing attempts can appear more trustworthy.
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