Post-login open redirect via incomplete path validation
Published Aug 20, 2026 · Updated Aug 20, 2026
Open redirect in Robert Acock Punk::OAuth2 before 0.03 allows remote attackers to send users off-site after a genuine login. The oauth2_login route stores the attacker-controlled return parameter after same_origin_path rejects double slashes and CR/LF but accepts backslashes and tabs that browsers normalize into a cross-origin authority. Exploitation requires a victim to follow a crafted application login link and finish authentication; the final redirect exposes no authorization code or access token.
Summary
What happened
Open redirect in Robert Acock Punk::OAuth2 before 0.03 allows remote attackers to send users off-site after a genuine login. The oauth2_login route stores the attacker-controlled return parameter after same_origin_path rejects double slashes and CR/LF but accepts backslashes and tabs that browsers normalize into a cross-origin authority. Exploitation requires a victim to follow a crafted application login link and finish authentication; the final redirect exposes no authorization code or access token.
The record
- CVE
- CVE-2026-75628
- Published
- Aug 20, 2026
- Updated
- Aug 20, 2026
- Vendor
- Robert Acock
- Product
- Punk::OAuth2
- 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 20, 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=0 <0.03
What conditions does exploitation require?
What is affected?
Published CVSS scores
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CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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