Open redirect via control-prefixed Location normalization
Published Aug 20, 2026 · Updated Aug 25, 2026
Open redirect in Pylons Project WebOb before 1.8.11 allows remote attackers to send users off-host through a crafted redirect target. Location handling checks the unstripped value before urllib.parse.urljoin removes leading C0 controls or spaces and interprets the remainder as an absolute or protocol-relative URL. Exploitation requires control over an application's redirect target and a user to follow the redirect; consequences include phishing and OAuth or SSO token theft.
Summary
What happened
Open redirect in Pylons Project WebOb before 1.8.11 allows remote attackers to send users off-host through a crafted redirect target. Location handling checks the unstripped value before urllib.parse.urljoin removes leading C0 controls or spaces and interprets the remainder as an absolute or protocol-relative URL. Exploitation requires control over an application's redirect target and a user to follow the redirect; consequences include phishing and OAuth or SSO token theft.
The record
- CVE
- CVE-2026-54770
- Published
- Aug 20, 2026
- Updated
- Aug 25, 2026
- Vendor
- Pylons Project
- Product
- WebOb
- Classifications
- CWE-601, T1204.001
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 20, 2026CVE publishedPublication date reported by the CVE source.
- Aug 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 1.8.11
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Leading-space Location proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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