CVE-2026-41059Network attack vector

Unauthenticated upstream access via fragment-confused allowlist matching

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 upstream resources. Skip-auth matching evaluates a path containing # or %23 against a widened public-route pattern, while the upstream interprets the suffix as a fragment and serves the protected base path. Exposure requires skip_auth_routes or skip_auth_regex, a suffix-widenable pattern, and an upstream that treats the number sign as a fragment delimiter or routes to the base path.

CVSS severity8.2
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Authentication bypass in OAuth2 Proxy 7.5.0 through 7.15.1 allows remote attackers to access protected upstream resources. Skip-auth matching evaluates a path containing # or %23 against a widened public-route pattern, while the upstream interprets the suffix as a fragment and serves the protected base path. Exposure requires skip_auth_routes or skip_auth_regex, a suffix-widenable pattern, and an upstream that treats the number sign as a fragment delimiter or routes to the base path.

The record

CVE
CVE-2026-41059
Published
Apr 21, 2026
Updated
Apr 21, 2026
Vendor
OAuth2 Proxy
Product
OAuth2 Proxy
Classifications
CWE-288, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

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

8.2GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/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-288Authentication Bypass Using an Alternate Path or Channel
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo