CVE-2026-18215

HIGHNVD 8.18.1
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 8.1 under NVD CVSS v3. EPSS exploit probability: 0.4% (34th percentile of EPSS-scored CVEs). GitHub Security Advisory CVSS 6.8 is lower than this score; a lower GitHub score revises it only when its advisory is newer than the CVE record's last change, and this advisory (published 2026-07-31) is not newer than that change (2026-09-16), so it does not.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 4 sources updated this week

Also known asEUVD-2026-51480 (ENISA EUVD) · GHSA-v8h5-7wp9-qxxv (GitHub Security Advisories)Source: ENISA EUVD

8.1EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 8.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Keycloak provides a way to let users log in using Microsoft accounts while restricting access to a specific organization (tenant). A flaw was discovered where this restriction is ignored when using the token exchange feature. This means an attacker with a valid Microsoft token from a completely different organization could gain access to the Keycloak realm, potentially accessing sensitive data or performing unauthorized actions.

CVSS v3
8.1
EG Score
8.1HIGHmedium confidence
EG Risk
37
EG Risk 37/100

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)
Severity81% × 45%
Impact severity (EG Severity): CVSS 8.1 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (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.
EPSS PROB
0.4%
EPSS %ILE
34th
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 (8.1): severity, escalated by confirmed exploitation. This CVE's 8.1 is its impact severity (EG Severity), not escalated.

EG Severity
8.1 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-30). 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; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade 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; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (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)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (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

July 31, 2026

Last Modified

September 16, 2026

Advisory Details (2)

Auto-updated Jul 31, 2026
Patch available. Sources: redhat.
Red Hat

2508309 – (CVE-2026-18215) CVE-2026-18215 keycloak-services: keycloak-services: Microsoft external access-token exchange bypasses configured tenant

https://bugzilla.redhat.com/show_bug.cgi?id=2508309
Red HatMentions a patch (unverified)

cve-details

https://access.redhat.com/security/cve/CVE-2026-18215

Vendor Advisories for CVE-2026-18215(3)

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
redhatrhbk/keycloak-rhel9-operator:26.6-202026-09-16redhat
redhatrhbk-openshift-rhel9/rhbk-openshift-rhel92026-09-16redhat

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.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 56× 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 it from the CNA feed. 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). Most recent first.

Showing the most recent 100 of 282 refreshes 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 182 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-02 16:44 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  2. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  3. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  4. 2026-10-31 02:04 UTCEG score recompute
  5. 2026-10-31 02:04 UTCVendor advisory
  6. 2026-10-31 02:04 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  7. 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  8. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  9. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  10. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  11. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  12. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  13. 2026-10-25 14:45 UTCEG score recompute
  14. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  15. 2026-10-24 09:58 UTCEG score recompute
  16. 2026-10-24 09:58 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  17. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  18. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  19. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  20. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  21. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  22. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  23. 2026-10-18 03:59 UTCEG score recompute
  24. 2026-10-17 17:51 UTCEG score recompute
  25. 2026-10-17 17:51 UTCVendor advisory
Show 75 more
  1. 2026-10-17 17:51 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  2. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  3. 2026-10-16 16:40 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  4. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  5. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  6. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  7. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  8. 2026-10-12 16:27 UTCEG score recompute
  9. 2026-10-11 20:07 UTCEG score recompute
  10. 2026-10-11 17:20 UTCEG score recompute
  11. 2026-10-11 14:52 UTCEG score recompute
  12. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  13. 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  14. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  15. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  16. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  17. 2026-10-06 23:51 UTCEG score recompute
  18. 2026-10-06 23:51 UTCVendor advisory
  19. 2026-10-06 23:51 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  20. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  21. 2026-10-05 19:57 UTCEG score recompute
  22. 2026-10-05 19:57 UTCVendor advisory
  23. 2026-10-05 19:56 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  24. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  25. 2026-10-04 23:52 UTCEG score recompute
  26. 2026-10-04 23:52 UTCVendor advisory
  27. 2026-10-04 23:52 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  28. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  29. 2026-10-04 06:33 UTCEG score recompute
  30. 2026-10-04 06:33 UTCVendor advisory
  31. 2026-10-04 06:33 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  32. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  33. 2026-10-02 16:52 UTCEG score recompute
  34. 2026-10-02 16:52 UTCVendor advisory
  35. 2026-10-02 16:52 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  36. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  37. 2026-10-01 13:58 UTCVendor advisory
  38. 2026-10-01 13:58 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  39. 2026-10-01 02:48 UTCEG score recompute
  40. 2026-10-01 02:48 UTCVendor advisory
  41. 2026-10-01 02:48 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  42. 2026-09-30 15:02 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  43. 2026-09-29 15:20 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  44. 2026-09-29 06:50 UTCEG score recompute
  45. 2026-09-29 06:50 UTCVendor advisory
  46. 2026-09-29 06:50 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  47. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  48. 2026-09-28 06:02 UTCVendor advisory
  49. 2026-09-28 06:02 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  50. 2026-09-27 18:57 UTCEG score recompute
  51. 2026-09-27 18:57 UTCVendor advisory
  52. 2026-09-27 18:57 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  53. 2026-09-27 13:47 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  54. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  55. 2026-09-25 04:53 UTCEG score recompute
  56. 2026-09-25 04:53 UTCVendor advisory
  57. 2026-09-25 04:53 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  58. 2026-09-24 10:59 UTCVendor advisory
  59. 2026-09-24 10:59 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  60. 2026-09-23 23:54 UTCEG score recompute
  61. 2026-09-23 23:54 UTCVendor advisory
  62. 2026-09-23 23:54 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  63. 2026-09-23 11:38 UTCVendor advisory
  64. 2026-09-23 11:38 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  65. 2026-09-23 00:32 UTCEG score recompute
  66. 2026-09-23 00:32 UTCVendor advisory
  67. 2026-09-23 00:32 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  68. 2026-09-22 13:23 UTCEG score recompute
  69. 2026-09-22 13:23 UTCVendor advisory
  70. 2026-09-22 13:23 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  71. 2026-09-20 11:09 UTCVendor advisory
  72. 2026-09-20 11:09 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8
  73. 2026-09-19 23:43 UTCEG score recompute
  74. 2026-09-19 23:43 UTCVendor advisory
  75. 2026-09-19 23:43 UTCGHSA enrichmentGHSA-v8h5-7wp9-qxxv · GitHub CVSS 6.8

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Frequently asked(5)

What is CVE-2026-18215?
CVE-2026-18215 is a high-severity vulnerability; its CVE record was published on July 31, 2026. Keycloak provides a way to let users log in using Microsoft accounts while restricting access to a specific organization (tenant). A flaw was discovered where this restriction is ignored when using the token exchange feature. This means an attacker with a valid Microsoft token from a completely…
When was CVE-2026-18215 made public?
CVE-2026-18215 was made public on July 28, 2026: that is the date its CVE record's CNA, Red Hat, Inc., gives for when the vulnerability was made public. The CVE record itself was published on July 31, 2026. EchelonGraph's copy of the record carries a last-modified date of September 16, 2026; the record at its source may have been updated since.
Is CVE-2026-18215 actively exploited?
CVE-2026-18215 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (34th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-18215?
CVE-2026-18215 has a CVSS v3 base score of 8.1 (NVD).
How do I remediate CVE-2026-18215?
A fix for CVE-2026-18215 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-18215 are linked in the Vendor Advisories panel on this page.

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