CVE-2026-40575Network attack vector

Authentication bypass via spoofed forwarded URI

Published Apr 21, 2026 · Updated Apr 21, 2026

Authentication bypass in OAuth2 Proxy 7.5.0 through 7.15.1 allows remote attackers to access protected routes without a session. With reverse-proxy mode enabled, skip-auth evaluation trusts a client-controlled X-Forwarded-Uri path instead of the URI sent upstream. Exposure requires reverse-proxy mode plus at least one skip-auth route or regular expression, and grants the unauthenticated request the protected route's access.

CVSS severity9.1
Critical
EPSS probability0.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in OAuth2 Proxy 7.5.0 through 7.15.1 allows remote attackers to access protected routes without a session. With reverse-proxy mode enabled, skip-auth evaluation trusts a client-controlled X-Forwarded-Uri path instead of the URI sent upstream. Exposure requires reverse-proxy mode plus at least one skip-auth route or regular expression, and grants the unauthenticated request the protected route's access.

The record

CVE
CVE-2026-40575
Published
Apr 21, 2026
Updated
Apr 21, 2026
Vendor
OAuth2 Proxy
Product
OAuth2 Proxy
Classifications
CWE-290, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 21, 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.

  1. Affected versionversion=>= 7.5.0, < 7.15.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OAuth2 Proxy · OAuth2 Proxyversion=>= 7.5.0, < 7.15.2

Published CVSS scores

9.1GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
8.7Red HatCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-290Authentication Bypass by Spoofing
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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