CVE-2026-54770
WebOb: Open redirect in Location header normalization via leading C0 control / space characters
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.
INFO
Published Date :
Aug. 20, 2026, 5:18 p.m.
Last Modified :
Oct. 18, 2026, 8:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE |
Solution
- Update WebOb to version 1.8.11.
- Ensure redirect targets are properly validated.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-54770.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-54770 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-54770
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-54770 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-54770 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 18, 2026
Action Type Old Value New Value Added Translation Title: webob de Pylons, Description: WebOb proporciona objetos para solicitudes y respuestas HTTP. Antes de la versión 1.8.11, Response._make_location_absolute() en src/webob/response.py verifica un valor de Location en busca de un esquema URI o una doble barra inicial antes de que urllib.parse.urljoin() elimine los caracteres de control C0 iniciales y los espacios. Un valor controlado por el atacante, como un espacio seguido de una URL relativa al protocolo o absoluta, puede, por lo tanto, eludir las comprobaciones de SCHEME_RE y startswith(“//”) y ser normalizado a una redirección fuera del host. Request.relative_url() y las subclases de webob.exc._HTTPMove, incluyendo HTTPFound, también se ven afectadas porque utilizan el mismo comportamiento inseguro de unión de URL o eluden la ruta de normalización anterior. Un atacante no autenticado que puede influir en el objetivo de redirección de una aplicación puede enviar a los usuarios a un host controlado por el atacante para phishing o robo de tokens de OAuth y SSO, pero la explotación requiere que el usuario siga la redirección. Este problema se ha solucionado en la versión 1.8.11. -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Aug. 25, 2026
Action Type Old Value New Value Added Reference https://github.com/Pylons/webob/security/advisories/GHSA-6hx8-3wjj-gr8g Added SSVC {'id': 'CVE-2026-54770', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-08-25T15:03:54.011941Z'} -
New CVE Received by [email protected]
Aug. 20, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Pylons', 'product': 'webob', 'versions': [{'status': 'affected', 'version': '< 1.8.11'}]}] Added 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Added CWE CWE-601 Added Reference https://github.com/Pylons/webob/commit/ff89560643fb252751b4db8806a283b5377f1f07 Added Reference https://github.com/Pylons/webob/security/advisories/GHSA-6hx8-3wjj-gr8g Added Reference https://github.com/Pylons/webob/tree/1.8.11