CVE-2026-76835

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreHIGH confidence

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-08-24. a secondary CVSS source baseline 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this weekElevated
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.1Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

OAuth2 Proxy honours a client-supplied X-Forwarded-Uri header when deciding whether a request may skip authentication, because the guard added for CVE-2026-40575 is inert in the default reverse-proxy configuration. GetRequestURI in pkg/requests/util/util.go prefers that header over the real request URI whenever CanTrustForwardedHeaders returns true, and isAllowedPath in oauthproxy.go matches the skip_auth_routes and skip_auth_regex allow list against the resulting path. CanTrustForwardedHeaders in pkg/apis/middleware/scope.go grants that trust when the caller's address is in the trusted proxy set, and buildTrustedProxyNetSet falls back to defaultTrustedProxyIPs, which is 0.0.0.0/0 and ::/0, whenever reverse proxy mode is enabled without trusted_proxy_ip configured. Every client is therefore treated as a trusted proxy. An unauthenticated attacker can request a protected upstream path while setting X-Forwarded-Uri to a value matching an allow-listed route, so the skip-auth decision is made against the spoofed value while the upstream receives the protected path unchanged.

CVSS v3
9.1
EG Score
9.1(high)
EG Risk
72(Attend)
EG Risk 72/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity91% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
27%
KEV
Not listed

Published

August 24, 2026

Last Modified

August 24, 2026

Advisory Details (5)

Auto-updated Aug 24, 2026
Patch available. Sources: github.
generic

OAuth2 Proxy 7.15.2 through 7.15.4 Authentication Bypass via X-Forwarded-Uri Under the Default Trusted Proxy Set | Advisories | VulnCheck

https://www.vulncheck.com/advisories/oauth2-proxy-through-authentication-bypass-via-x-forwarded-uri-under-the-default-trusted-proxy-set
github Patch Available

Authentication Bypass via X-Forwarded-Uri Header Spoofing · Advisory · oauth2-proxy/oauth2-proxy · GitHub

https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-7x63-xv5r-3p2x
generic

oauth2-proxy/pkg/apis/middleware/scope.go at v7.15.4 · oauth2-proxy/oauth2-proxy · GitHub

https://github.com/oauth2-proxy/oauth2-proxy/blob/v7.15.4/pkg/apis/middleware/scope.go
generic

[Bug]: Auth bypass: spoofed X-Forwarded-Uri skips auth for protected upstream paths under default reverse-proxy config · Issue #3506 · oauth2-proxy/oauth2-proxy · GitHub

https://github.com/oauth2-proxy/oauth2-proxy/issues/3506
generic

GitHub - oauth2-proxy/oauth2-proxy: A reverse proxy that provides authentication with Google, Azure, OpenID Connect and many more identity providers. · GitHub

https://github.com/oauth2-proxy/oauth2-proxy

Vendor Advisories for CVE-2026-76835(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(2 across 1 ecosystem)
Go(2)
PackageVulnerable rangeFixed inDependents
github.com/oauth2-proxy/oauth2-proxy———
github.com/oauth2-proxy/oauth2-proxy/v7—7.15.2—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 25× in last 7d / 25× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-26 19:51 UTCGHSA enrichment
  2. 2026-08-26 16:13 UTCEG score recompute
  3. 2026-08-26 16:13 UTCGHSA enrichment
  4. 2026-08-26 14:47 UTCEPSS rescore
  5. 2026-08-26 12:24 UTCGHSA enrichment
  6. 2026-08-26 08:43 UTCGHSA enrichment
  7. 2026-08-26 05:05 UTCGHSA enrichment
  8. 2026-08-26 01:25 UTCGHSA enrichment
  9. 2026-08-25 21:48 UTCGHSA enrichment
  10. 2026-08-25 18:11 UTCGHSA enrichment
  11. 2026-08-25 14:33 UTCEG score recompute
  12. 2026-08-25 14:33 UTCGHSA enrichment
  13. 2026-08-25 13:49 UTCEPSS rescore
  14. 2026-08-25 10:56 UTCGHSA enrichment
  15. 2026-08-25 07:18 UTCGHSA enrichment
  16. 2026-08-25 03:40 UTCGHSA enrichment
  17. 2026-08-25 00:03 UTCEG score recompute
  18. 2026-08-25 00:03 UTCGHSA enrichment
  19. 2026-08-24 20:26 UTCEG score recompute
  20. 2026-08-24 20:26 UTCGHSA enrichment
  21. 2026-08-24 20:12 UTCEG score recompute
  22. 2026-08-24 20:11 UTCGHSA enrichment
  23. 2026-08-24 18:21 UTCEG score recompute
  24. 2026-08-24 18:01 UTCEG score recompute
  25. 2026-08-24 18:01 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-76835?
CVE-2026-76835 is a critical vulnerability published on August 24, 2026. OAuth2 Proxy honours a client-supplied X-Forwarded-Uri header when deciding whether a request may skip authentication, because the guard added for CVE-2026-40575 is inert in the default reverse-proxy configuration. GetRequestURI in pkg/requests/util/util.go prefers that header over the real request…
When was CVE-2026-76835 disclosed?
CVE-2026-76835 was first published in the National Vulnerability Database on August 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-76835 actively exploited?
CVE-2026-76835 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 72.6% of all scored CVEs.
What is the CVSS score of CVE-2026-76835?
CVE-2026-76835 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-76835?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-76835, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-76835

Explore →

Is Your Infrastructure Affected by CVE-2026-76835?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs