CVE-2026-54770

A flaw was found in WebOb, a library for HTTP requests and responses. This vulnerability allows an unauthenticated attacker to bypass URL validation checks by injecting leading control characters or spaces into a redirect target. This can lead to an open redirect, enabling attackers to send users to malicious websites for phishing or to steal OAuth and Single Sign-On (SSO) tokens. Exploitation requires the user to follow the crafted redirect.

This is an open redirect vulnerability in the WebOb library. An unauthenticated attacker can craft a malicious URL that, when processed by applications utilizing WebOb for redirects, bypasses URL validation. This could lead to users being redirected to attacker-controlled sites, facilitating phishing attacks or the theft of authentication tokens, provided the user follows the redirect.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Applications utilizing the WebOb library should implement strict validation of redirect target URLs. Configure applications to only allow redirects to trusted, fully-qualified URIs or to strictly allowlist permitted redirect destinations. Reject any redirect target that does not begin with an expected trusted host or a validated relative path, ensuring no leading whitespace or control characters are present.