Pylons WebOb up to 1.8.10 src/webob/response.py Response._make_location_absolute Location redirect

Summaryinfo

A vulnerability labeled as problematic has been found in Pylons WebOb up to 1.8.10. Affected is the function Response._make_location_absolute of the file src/webob/response.py. Such manipulation of the argument Location leads to redirect. This vulnerability is listed as CVE-2026-54770. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Pylons WebOb up to 1.8.10. Affected by this issue is the function Response._make_location_absolute of the file src/webob/response.py. The manipulation of the argument Location with an unknown input leads to a redirect vulnerability. Using CWE to declare the problem leads to CWE-601. A web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a Redirect. This simplifies phishing attacks. Impacted is integrity. CVE summarizes:

WebOb provides objects for HTTP requests and responses. Prior to 1.8.11, Response._make_location_absolute() in src/webob/response.py checks a Location value for a URI scheme or leading double slash before urllib.parse.urljoin() strips leading C0 control characters and spaces. An attacker-controlled value such as a space followed by a protocol-relative or absolute URL can therefore bypass SCHEME_RE and startswith("//") checks and be normalized to an off-host redirect. Request.relative_url() and webob.exc._HTTPMove subclasses, including HTTPFound, are also affected because they use the same unsafe URL joining behavior or bypass the earlier normalization path. An unauthenticated attacker who can influence an application's redirect target can send users to an attacker-controlled host for phishing or OAuth and SSO token theft, but exploitation requires the user to follow the redirect. This issue is fixed in version 1.8.11.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-54770 since 06/16/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1204.001.

Upgrading to version 1.8.11 eliminates this vulnerability.

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Productinfo

Vendor

• Pylons

Name

• WebOb

Version

• 1.8.0
• 1.8.1
• 1.8.2
• 1.8.3
• 1.8.4
• 1.8.5
• 1.8.6
• 1.8.7
• 1.8.8
• 1.8.9
• 1.8.10

Website

• Product: https://github.com/Pylons/webob/

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