highCVSS 8.2Vulnerability

GHSA-pxq7-h93f-9jrg

### Impact A configuration-dependent authentication bypass exists in OAuth2 Proxy. Deployments are affected when all of the following are true: * Use of `skip_auth_routes` or the legacy `skip_auth_regex` * Use of patterns that can be widened by attacker-controlled suffixes, such as `^/foo/.*/bar$` causing potential exposure of `/foo/secret` * Protected upstream applications that interpret `#` as a fragment delimiter or otherwise route the request to the protected base path In deployments that rely on these settings, an unauthenticated attacker can send a crafted request containing a number sign in the path, including the browser-safe encoded form `%23`, so that OAuth2 Proxy matches a public allowlist rule while the backend serves a protected resource. Deployments that do not use these skip-auth options, or that only allow exact public paths with tightly scoped method and path rules, **ARE NOT** affected. ### Patches A fix has been implemented to normalize request paths more conservatively before skip-auth matching so fragment content does not influence allowlist decisions. Released as part of `v7.15.2` ### Workarounds Users who cannot upgrade immediately can reduce exposure by tightening or removing `skip_auth_routes` and `skip_auth_regex` rules, especially patterns that use broad wildcards across path segments. Recommended mitigations: * Replace broad rules with exact, anchored public paths and explicit HTTP methods * Reject requests whose path contains `%23` or `#` at the ingress, load balancer, or WAF level * Avoid placing sensitive application paths behind broad `skip_auth_routes` rules

Properties

ghsa_id
GHSA-pxq7-h93f-9jrg
summary
OAuth2 Proxy has an Authentication Bypass via Fragment Confusion in skip_auth_routes and skip_auth_regex
severity
high
cvss_score
8.2
cve_id
GHSA-pxq7-h93f-9jrg
cvss_vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
is_ghsa_only
true
ghsa_published
2026-04-15T19:24:13Z
source_url
https://github.com/advisories/GHSA-pxq7-h93f-9jrg
ghsa_updated
2026-04-15T19:24:13Z

Related Entities (4)

HAS_WEAKNESS (1)

[Weakness]Authentication Bypass Using an Alternate Path or Channel

REPORTED_BY (1)

[Source]GitHub Advisory Database

VULNERABLE_TO (1)

[Software]go/github.com/oauth2-proxy/oauth2-proxy/v7

AFFECTS (1)

[Software]go/github.com/oauth2-proxy/oauth2-proxy/v7

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GHSA-pxq7-h93f-9jrg (CVSS 8.2) — Ninja Signal Threat Intelligence | Ninja Signal