Unauthenticated route access via spoofed forwarded URI
Published Aug 24, 2026 · Updated Aug 24, 2026
Authentication bypass in OAuth2 Proxy 7.15.2 through 7.15.4 allows remote attackers to access protected routes via a spoofed X-Forwarded-Uri header. GetRequestURI trusts that header from every client under the default proxy set, and isAllowedPath evaluates skip-auth rules against the spoofed path while forwarding the original protected path. Exploitation requires reverse-proxy mode, an unset trusted_proxy_ip value, and at least one skip_auth_routes or skip_auth_regex rule; successful requests reach protected upstream content without a session.
Summary
What happened
Authentication bypass in OAuth2 Proxy 7.15.2 through 7.15.4 allows remote attackers to access protected routes via a spoofed X-Forwarded-Uri header. GetRequestURI trusts that header from every client under the default proxy set, and isAllowedPath evaluates skip-auth rules against the spoofed path while forwarding the original protected path. Exploitation requires reverse-proxy mode, an unset trusted_proxy_ip value, and at least one skip_auth_routes or skip_auth_regex rule; successful requests reach protected upstream content without a session.
The record
- CVE
- CVE-2026-76835
- Published
- Aug 24, 2026
- Updated
- Aug 24, 2026
- Vendor
- OAuth2 Proxy
- Product
- OAuth2 Proxy
- Classifications
- CWE-290, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 24, 2026CVE publishedPublication date reported by the CVE source.
- Aug 24, 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=7.15.2 <=7.15.4
What conditions does exploitation require?
What is affected?
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
- OAuth2 Proxy issue 3506 proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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