Bug 2491570 (CVE-2026-44889)

Summary: CVE-2026-44889 webob: python-webob: WebOb: Open Redirect vulnerability via HTTP Location header normalization
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: amctagga, aoconnor, bdettelb, bniver, doconnor, eglynn, flucifre, gmeno, groman, jjoyce, jpretori, jschluet, lhh, mbenjamin, mburns, mgarciac, mhackett, rhel-process-autobot, sostapov, teagle, vereddy, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in WebOb, a library for HTTP requests and responses. A remote attacker could exploit this vulnerability by influencing the HTTP Location header during a redirect. Due to improper normalization of the Location header, specifically how certain ASCII characters are handled, an attacker can cause a user to be redirected to an arbitrary external website instead of the intended destination. This open redirect vulnerability can lead to information disclosure and impact the integrity of user sessions.
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Description OSIDB Bzimport 2026-06-22 22:03:11 UTC 
WebOb provides objects for HTTP requests and responses. Prior to 1.8.10, the normalization of the HTTP Location header during a redirect is vulnerable to an open redirect: WebOb joins the redirect target to the request URI using Python's urljoin, and since Python 3.10 the underlying urlsplit strips ASCII tab, carriage return, and newline characters before parsing, so a redirect target containing such characters can be reinterpreted as a protocol-relative URL whose authority is an attacker-controlled host. This bypasses the CVE-2024-42353 fix that escaped a leading double slash, allowing an attacker who influences the redirect location to send users to an arbitrary external site instead of the intended one. This vulnerability is fixed in 1.8.10.