CVE-2026-9087
📛 CVE Title
Keycloak: cross-session email verification proof not bound to upstream identity in first-broker-login
Description
A flaw was found in Keycloak. The cross-session verification proof is keyed only by (local userId, idpAlias) and is not bound to the upstream identity that was actually verified, so a second upstream account on the same IdP can consume it and get linked to the victim's local account.
Overview
- State
- PUBLISHED
- Assigner (CNA)
- redhat
- CVSS severity
- MEDIUM
- CVSS score
- 6.4 / 10
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N- Effective score
- 6.4 / 10 MEDIUM source: CNA overview
- CWE(s)
-
CWE-639 - Reserved
- 2026-05-20
- Published
- 2026-05-20 16:13 UTC
- Last updated
- 2026-05-20 16:13 UTC
- Source
- https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/9xxx/CVE-2026-9087.json
- Linked Threat
- CVE-2026-9087 — CVE-2026-9087
NVD triage scoring NVD CVE 2.0
Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.
- NVD published
- 2026-05-20 17:16:32 UTC
- NVD last modified
- 2026-05-20 17:32:35 UTC
- NVD CVSS v3.1
- 6.4 / 10 MEDIUM source: secalert@redhat.com
- NVD CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N- Exploitability subscore
- 1.2 / 10
- Impact subscore
- 5.2 / 10
- EPSS score
- 0.0003 (probability of exploitation in next 30 days)
- EPSS percentile
- 8.40% vs all CVEs — higher = more likely to be exploited, as of 2026-05-24
NVD / KEV / EPSS data refreshed 2026-05-25 00:32 UTC. Re-run the 🛰 Backfill from NVD button above to refresh.
European Union Vulnerability Database ENISA EUVD
ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.
- EUVD ID
-
EUVD-2026-31134 - Assigner
- redhat
- Published
- May 20, 2026, 4:13:03 PM
- Updated
- May 21, 2026, 2:02:09 PM
- EUVD base score (CVSS 3.1)
-
6.4 / 10
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N - EUVD-reported EPSS
- 0.0300
- Aliases
-
GHSA-m6qj-3mpp-57v8
ENISA description: A flaw was found in Keycloak. The cross-session verification proof is keyed only by (local userId, idpAlias) and is not bound to the upstream identity that was actually verified, so a second upstream account on the same IdP can consume it and get linked to the victim's local account.
Affected products (1)
| Vendor | Product | Versions | Platforms |
|---|---|---|---|
| Red Hat | Red Hat Build of Keycloak | — | — |
Vendor references (2)
References embedded in the original CVE record by the assigning CNA.
- https://access.redhat.com/security/cve/CVE-2026-9087 vdb-entryx_refsource_REDHAT
- RHBZ#2480172 issue-trackingx_refsource_REDHAT
Web references (5)
DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.
- https://access.redhat.com/security/cve/CVE-2026-9087 tenable:access.redhat.com
- https://bugzilla.redhat.com/show_bug.cgi?id=2480172 tenable:bugzilla.redhat.com
- https://nvd.nist.gov/vuln/detail/CVE-2026-9087 tenable:nvd.nist.gov
- https://www.cve.org/CVERecord?id=CVE-2026-9087 tenable:www.cve.org
- https://www.first.org/epss/ tenable:www.first.org
NVD-tagged references (2)
Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.
- https://access.redhat.com/security/cve/CVE-2026-9087 secalert@redhat.com
- https://bugzilla.redhat.com/show_bug.cgi?id=2480172 secalert@redhat.com
Remediations (17)
Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.
-
web:blog.qualys.com
Microsoft's February 2026 Patch Tuesday focuses on closing security gaps that attackers could exploit, reinforcing the importance of timely patching in enterprise environments. Here's a quick…
2026-05-23 22:18 UTC -
web:cybersecuritynews.com
Microsoft Exchange Server spoofing flaw, is being actively exploited against on-premises systems before a permanent patch is available.
2026-05-23 22:18 UTC -
web:krebsonsecurity.com
Microsoft expects that exploitation is more likely. May's Patch Tuesday is a welcome respite from April, which saw Microsoft fix a near-record 167 security flaws.
2026-05-23 22:18 UTC -
web:portal.msrc.microsoft.com
The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.
2026-05-23 22:18 UTC -
web:www.computerworld.com
Each month, the team at Readiness analyzes the latest Patch Tuesday updates from Microsoft and provides detailed, actionable testing guidance. The company's Patch Tuesday release for February ...
2026-05-23 22:18 UTC -
web:www.crowdstrike.com
Microsoft has released security updates for 114 vulnerabilities, including three zero-days, plus eight critical CVEs in its January 2026 Patch Tuesday rollout.
2026-05-23 22:18 UTC -
web:www.msn.com
Original story: Microsoft has released an emergency patch for a vulnerability in the company's Office programs that's already being exploited by hackers.
2026-05-23 22:18 UTC -
web:www.oracle.com
This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.
2026-05-23 22:18 UTC -
web:www.picussecurity.com
As exploitation activity has already been detected in the wild, making prompt remediation critical for all WSUS-enabled environments [2]. This blog examines the WSUS service, the root cause of CVE -2025-59287, available proof-of-concept exploits, and the recommended mitigation and workaround strategies.
2026-05-23 22:18 UTC -
web:zecurit.com
Get the complete breakdown of Microsoft's May 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .
2026-05-23 22:18 UTC -
web:blog.qualys.com
May 2026's Patch Tuesday arrives with Microsoft addressing a fresh set of vulnerabilities across its ecosystem, reinforcing the ongoing need for timely patching in an increasingly threat-heavy…
2026-06-05 11:47 UTC -
web:cybersecuritynews.com
Microsoft's May 2026 Patch Tuesday lands with a heavy enterprise focus, fixing 120 vulnerabilities across Windows, Office, Azure, developer tools, and Microsoft 365 apps, including 29 remote code execution (RCE) flaws rated Critical.
2026-06-05 11:47 UTC -
web:nvd.nist.gov
An official website of the United States government Here's how you know
2026-06-05 11:47 UTC -
web:support.microsoft.com
This out-of-band update for Windows 11, version 25H2 and 24H2 (KB5085518) includes fixes and improvements. To learn more about differences between security updates, optional non-security preview updates, out-of-band (OOB) updates, and continuous innovation, see Windows monthly updates explained. For information on Windows update terminology, see the different types of Windows software updates ...
2026-06-05 11:47 UTC -
web:www.cisa.gov
Updated October 29, 2025: CISA has updated this Alert to include revised information on vulnerable product identification, potential threat activity detections, and additional resources. Microsoft released an update to address a critical remote code execution vulnerability impacting Windows Server Update Service (WSUS) in Windows Server (2012, 2016, 2019, 2022, and 2025), CVE -2025-59287
2026-06-05 11:47 UTC -
web:www.pcworld.com
This month's Patch Tuesday includes an actively exploited Office zero-day vulnerability and several critical RCE bugs in Windows and Remote Desktop.
2026-06-05 11:47 UTC -
web:www.zdnet.com
Why you need Microsoft's new emergency Windows patch - and the black-screen bug to watch for While Microsoft has been fixing bugs caused by the Patch Tuesday update, another glitch has surfaced.
2026-06-05 11:47 UTC
AI Forensic Analysis
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Raw JSON
The full cvelistV5 record. Download as CVE-2026-9087.json.
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"cpes": [
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"defaultStatus": "affected",
"packageName": "rhbk/keycloak-rhel9",
"product": "Red Hat Build of Keycloak",
"vendor": "Red Hat"
}
],
"datePublic": "2026-05-20T14:53:44.238Z",
"descriptions": [
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}
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"metrics": [
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"value": "Moderate"
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},
{
"cvssV3_1": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 6.4,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N",
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"problemTypes": [
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"description": "Authorization Bypass Through User-Controlled Key",
"lang": "en",
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"providerMetadata": {
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"references": [
{
"tags": [
"vdb-entry",
"x_refsource_REDHAT"
],
"url": "https://access.redhat.com/security/cve/CVE-2026-9087"
},
{
"name": "RHBZ#2480172",
"tags": [
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"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2480172"
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"timeline": [
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"lang": "en",
"time": "2026-05-20T14:53:02.458Z",
"value": "Reported to Red Hat."
},
{
"lang": "en",
"time": "2026-05-20T14:53:44.238Z",
"value": "Made public."
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],
"title": "Keycloak: cross-session email verification proof not bound to upstream identity in first-broker-login",
"workarounds": [
{
"lang": "en",
"value": "To mitigate this issue, configure the affected identity provider to set `trustEmail=true`. This ensures that Keycloak trusts the email address provided by the upstream identity provider, bypassing the vulnerable verification flow. This mitigation should only be applied if the upstream identity provider is fully trusted to verify email addresses and prevent malicious account creation with existing email addresses. Configuration changes may require a Keycloak service restart or reload to take effect."
}
],
"x_generator": {
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},
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"dateReserved": "2026-05-20T14:53:18.352Z",
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