CVE-2026-40575

CRITICALPre-NVD 9.19.1
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-04-15. A secondary CVSS source baseline 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source

Also known asEUVD-2026-24557 (ENISA EUVD) · GHSA-7x63-xv5r-3p2x (GitHub Security Advisories) · GO-2026-5236 (OSV.dev)Source: ENISA EUVD

9.1EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 9.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

OAuth2 Proxy is a reverse proxy that provides authentication using OAuth2 providers. Versions 7.5.0 through 7.15.1 may trust a client-supplied X-Forwarded-Uri header when --reverse-proxy is enabled and --skip-auth-regex or --skip-auth-route is configured. An attacker can spoof this header so OAuth2 Proxy evaluates authentication and skip-auth rules against a different path than the one actually sent to the upstream application. This can result in an unauthenticated remote attacker bypassing authentication and accessing protected routes without a valid session. Impacted users are deployments that run oauth2-proxy with --reverse-proxy enabled and configure at least one --skip-auth-regex or --skip-auth-route rule. This issue is patched in v7.15.2. Some workarounds are available for those who cannot upgrade immediately. Strip any client-provided X-Forwarded-Uri header at the reverse proxy or load balancer level; explicitly overwrite X-Forwarded-Uri with the actual request URI before forwarding requests to OAuth2 Proxy; restrict direct client access to OAuth2 Proxy so it can only be reached through a trusted reverse proxy; and/or remove or narrow --skip-auth-regex / --skip-auth-route rules where possible. For nginx-based deployments, ensure X-Forwarded-Uri is set by nginx and not passed through from the client.

CVSS v3
9.1
EG Score
9.1CRITICALmedium confidence
EG Risk
56
EG Risk 56/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity91% × 45%
Impact severity (EG Severity): CVSS 9.1 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.5% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.5%
EPSS %ILE
41st
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (9.1): severity, escalated by confirmed exploitation. This CVE's 9.1 is its impact severity (EG Severity), not escalated.

EG Severity
9.1 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-12). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)3 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

April 22, 2026

Last Modified

November 11, 2026

Advisory Details (4)

Auto-updated Sep 16, 2026
Patch available. Sources: github, redhat.
Red Hat

2460449 – (CVE-2026-40575) CVE-2026-40575 oauth2-proxy: github.com/oauth2-proxy/oauth2-proxy: OAuth2 Proxy: Authentication bypass due to spoofed X-Forwarded-Uri header

https://bugzilla.redhat.com/show_bug.cgi?id=2460449
Red HatMentions a patch (unverified)

CVE-2026-40575 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2026-40575
GitHub advisoryMentions a patch (unverified)

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

Vendor Advisories for CVE-2026-40575(2)

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

Patch Availability(2)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatoauth2-proxy-main-7.15.4-0.1.hum12026-08-22redhat
gogithub.com/oauth2-proxy/oauth2-proxy/v7 @ 7.15.2 (fixes >= 7.5.0, < 7.15.2)—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(2 across 1 ecosystem)
Go(2)
PackageVulnerable rangeFix by version rangeDependents
github.com/oauth2-proxy/oauth2-proxy—
  • every version on: no fix on record
—
github.com/oauth2-proxy/oauth2-proxy/v7—
  • 7.5.0 up to 7.15.2: fixed in 7.15.2
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 23× in last 7d / 76× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 294 rows on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 194 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-12 22:45 UTCEchelonGraph re-scored
  2. 2026-11-12 22:45 UTCVendor advisory
  3. 2026-11-12 22:45 UTCGHSA enrichmentGHSA-7x63-xv5r-3p2x · GitHub severity CRITICAL · GitHub CVSS 9.1
  4. 2026-11-12 16:33 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  5. 2026-11-11 23:28 UTCVendor advisory
  6. 2026-11-11 23:28 UTCGHSA enrichmentGHSA-7x63-xv5r-3p2x · GitHub severity CRITICAL · GitHub CVSS 9.1
  7. 2026-11-11 19:09 UTCEchelonGraph re-scored
  8. 2026-11-11 19:09 UTCVendor advisory
  9. 2026-11-11 19:09 UTCGHSA enrichmentGHSA-7x63-xv5r-3p2x · GitHub severity CRITICAL · GitHub CVSS 9.1
  10. 2026-11-11 16:39 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  11. 2026-11-10 19:59 UTCEchelonGraph re-scored
  12. 2026-11-10 19:59 UTCVendor advisory
  13. 2026-11-10 19:59 UTCGHSA enrichmentGHSA-7x63-xv5r-3p2x · GitHub severity CRITICAL · GitHub CVSS 9.1
  14. 2026-11-10 16:43 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  15. 2026-11-09 20:49 UTCEchelonGraph re-scored
  16. 2026-11-09 20:49 UTCVendor advisory
  17. 2026-11-09 20:49 UTCGHSA enrichmentGHSA-7x63-xv5r-3p2x · GitHub severity CRITICAL · GitHub CVSS 9.1
  18. 2026-11-09 16:35 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  19. 2026-11-08 21:44 UTCEchelonGraph re-scored
  20. 2026-11-08 21:44 UTCVendor advisory
  21. 2026-11-08 21:44 UTCGHSA enrichmentGHSA-7x63-xv5r-3p2x · GitHub severity CRITICAL · GitHub CVSS 9.1
  22. 2026-11-08 16:39 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  23. 2026-11-07 22:38 UTCEchelonGraph re-scored
  24. 2026-11-07 22:38 UTCVendor advisory
  25. 2026-11-07 22:38 UTCGHSA enrichmentGHSA-7x63-xv5r-3p2x · GitHub severity CRITICAL · GitHub CVSS 9.1
Show 75 more
  1. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  2. 2026-11-06 23:31 UTCEchelonGraph re-scored
  3. 2026-11-06 23:31 UTCVendor advisory
  4. 2026-11-06 23:31 UTCGHSA enrichmentGHSA-7x63-xv5r-3p2x · GitHub severity CRITICAL · GitHub CVSS 9.1
  5. 2026-11-06 16:37 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  6. 2026-11-06 07:55 UTCOSV refresh
  7. 2026-11-06 00:26 UTCEchelonGraph re-scored
  8. 2026-11-06 00:26 UTCVendor advisory
  9. 2026-11-06 00:26 UTCGHSA enrichmentGHSA-7x63-xv5r-3p2x · GitHub severity CRITICAL · GitHub CVSS 9.1
  10. 2026-11-05 16:37 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  11. 2026-11-05 01:20 UTCEchelonGraph re-scored
  12. 2026-11-05 01:20 UTCVendor advisory
  13. 2026-11-05 01:20 UTCGHSA enrichmentGHSA-7x63-xv5r-3p2x · GitHub severity CRITICAL · GitHub CVSS 9.1
  14. 2026-11-04 16:35 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  15. 2026-11-04 02:14 UTCEchelonGraph re-scored
  16. 2026-11-04 02:14 UTCVendor advisory
  17. 2026-11-04 02:14 UTCGHSA enrichmentGHSA-7x63-xv5r-3p2x · GitHub severity CRITICAL · GitHub CVSS 9.1
  18. 2026-11-03 16:48 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  19. 2026-11-03 03:08 UTCEchelonGraph re-scored
  20. 2026-11-03 03:08 UTCVendor advisory
  21. 2026-11-03 03:08 UTCGHSA enrichmentGHSA-7x63-xv5r-3p2x · GitHub severity CRITICAL · GitHub CVSS 9.1
  22. 2026-11-02 16:44 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  23. 2026-11-02 04:02 UTCEchelonGraph re-scored
  24. 2026-11-02 04:02 UTCVendor advisory
  25. 2026-11-02 04:02 UTCGHSA enrichmentGHSA-7x63-xv5r-3p2x · GitHub severity CRITICAL · GitHub CVSS 9.1
  26. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  27. 2026-11-01 07:51 UTCGHSA enrichmentGHSA-7x63-xv5r-3p2x · GitHub severity CRITICAL · GitHub CVSS 9.1
  28. 2026-11-01 07:51 UTCEchelonGraph re-scored
  29. 2026-11-01 04:56 UTCEchelonGraph re-scored
  30. 2026-11-01 04:56 UTCVendor advisory
  31. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  32. 2026-10-31 05:50 UTCEchelonGraph re-scored
  33. 2026-10-31 05:50 UTCVendor advisory
  34. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  35. 2026-10-30 06:44 UTCEchelonGraph re-scored
  36. 2026-10-30 06:44 UTCVendor advisory
  37. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  38. 2026-10-29 07:38 UTCEchelonGraph re-scored
  39. 2026-10-29 07:38 UTCVendor advisory
  40. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  41. 2026-10-28 08:33 UTCEchelonGraph re-scored
  42. 2026-10-28 08:33 UTCVendor advisory
  43. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  44. 2026-10-27 09:05 UTCEchelonGraph re-scored
  45. 2026-10-27 09:05 UTCVendor advisory
  46. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  47. 2026-10-26 08:57 UTCEchelonGraph re-scored
  48. 2026-10-26 08:57 UTCVendor advisory
  49. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  50. 2026-10-25 14:30 UTCEchelonGraph re-scored
  51. 2026-10-25 09:52 UTCEchelonGraph re-scored
  52. 2026-10-25 09:52 UTCVendor advisory
  53. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  54. 2026-10-24 10:46 UTCEchelonGraph re-scored
  55. 2026-10-24 10:46 UTCVendor advisory
  56. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  57. 2026-10-23 11:40 UTCEchelonGraph re-scored
  58. 2026-10-23 11:40 UTCVendor advisory
  59. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  60. 2026-10-22 12:32 UTCEchelonGraph re-scored
  61. 2026-10-22 12:32 UTCVendor advisory
  62. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  63. 2026-10-21 13:27 UTCEchelonGraph re-scored
  64. 2026-10-21 13:27 UTCVendor advisory
  65. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  66. 2026-10-20 14:19 UTCEchelonGraph re-scored
  67. 2026-10-20 14:19 UTCVendor advisory
  68. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  69. 2026-10-19 13:22 UTCEchelonGraph re-scored
  70. 2026-10-19 13:22 UTCVendor advisory
  71. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  72. 2026-10-18 12:46 UTCVendor advisory
  73. 2026-10-18 03:42 UTCEchelonGraph re-scored
  74. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  75. 2026-10-17 13:40 UTCEchelonGraph re-scored

Frequently asked(5)

What is CVE-2026-40575?
CVE-2026-40575 is a critical-severity vulnerability; its CVE record was published on April 22, 2026. OAuth2 Proxy is a reverse proxy that provides authentication using OAuth2 providers. Versions 7.5.0 through 7.15.1 may trust a client-supplied X-Forwarded-Uri header when --reverse-proxy is enabled and --skip-auth-regex or --skip-auth-route is configured. An attacker can spoof this header so OAuth2…
When was the CVE record for CVE-2026-40575 published?
The CVE record for CVE-2026-40575 was published on April 22, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of November 11, 2026; the record at its source may have been updated since.
Is CVE-2026-40575 actively exploited?
CVE-2026-40575 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (41st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-40575?
CVE-2026-40575 has a CVSS base score of 9.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-40575?
A fix for CVE-2026-40575 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-40575 are linked in the Vendor Advisories panel on this page.

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