Vulnerability Description
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.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/Pylons/webob/commit/ff89560643fb252751b4db8806a283b5377f1f07
- https://github.com/Pylons/webob/security/advisories/GHSA-6hx8-3wjj-gr8g
- https://github.com/Pylons/webob/tree/1.8.11
FAQ
What is CVE-2026-54770?
CVE-2026-54770 is a vulnerability with a CVSS score of 6.1 (MEDIUM). 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 be...
How severe is CVE-2026-54770?
CVE-2026-54770 has been rated MEDIUM with a CVSS base score of 6.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-54770?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.