CVE-2025-54576: OAuth2-Proxy has authentication bypass in oauth2-proxy skip_auth_routes due to Query Parameter inclusion

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 1.2%, percentile 68: FIRST’s model estimates a 1.2% chance of exploitation activity in the next 30 days, higher than 68% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes github.com/oauth2-proxy/oauth2-proxy/v7 (Go) <= 7.10.0, fixed in 7.11.0. Check your lockfile, including transitive dependencies.

What it is

OAuth2-Proxy is an open-source tool that can act as either a standalone reverse proxy or a middleware component integrated into existing reverse proxy or load balancer setups. In versions 7.10.0 and below, oauth2-proxy deployments are vulnerable when using the skipauthroutes configuration option with regex patterns. Attackers can bypass authentication by crafting URLs with query parameters that satisfy configured regex patterns, allowing unauthorized access to protected resources. The issue stems from skipauthroutes matching against the full request URI. Deployments using skipauthroutes with regex patterns containing wildcards or broad matching patterns are most at risk. This issue is fixed in version 7.11.0. Workarounds include: auditing all skipauthroutes configurations for overly permissive patterns, replacing wildcard patterns with exact path matches where possible, ensuring regex patterns are properly anchored (starting with ^ and ending with $), or implementing custom validation that strips query parameters before regex matching.

From the GitHub advisory

Impact This vulnerability affects oauth2-proxy deployments using the skipauthroutes configuration option with regex patterns. The vulnerability allows attackers to bypass authentication by crafting URLs with query parameters that satisfy the configured regex patterns, potentially gaining unauthorized access to protected resources.

The issue stems from skipauthroutes matching against the full request URI (path + query parameters) instead of just the path as documented. This discrepancy enables authentication bypass attacks where attackers append malicious query parameters to access protected endpoints.

Example Attack:

Configuration: skipauthroutes = [ "^/foo/./bar$" ] Intended behavior: Allow /foo/something/bar Actual vulnerability: Also allows /foo/criticalendpoint?param=/bar

Deployments using skipauthroutes with regex patterns containing wildcards or broad matching patterns are most at risk, especially when backend services ignore unknown query parameters.

Weakness type: CWE-290.

Product: github.com/oauth2-proxy/oauth2-proxy/v7 (Go) · Assigned by: GitHub_M · Published: 2025-07-30

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 1.20% probability of exploitation activity in the next 30 days; percentile 68.

Timeline

• 2025-07-30 — CVE record last updated
• 2025-07-30 — CVE record published by GitHub_M
• 2025-07-30 — GitHub-reviewed advisory GHSA-7rh7-c77v-6434 published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-7rh7-c77v-6434 github.com
2. CVE.org record CVE-2025-54576 cve.org
3. NVD entry CVE-2025-54576 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com
4. github.com github.com
5. github.com github.com
6. oauth2-proxy.github.io oauth2-proxy.github.io

Critical Go advisories · Today’s Security Digest