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Advisory details: vulnrichment / CVE-2026-9087
Advisory ID vulnrichment/CVE-2026-9087
Aliases
Summary 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.
Status Published
Exploitability 0.5
Weighted Severity 0.0
Risk
Affected and Fixed Packages Package Details
Introduced and Fixed Package Commit Patches Package Commit Patches Details
Weaknesses (1)
CWE-639 Authorization Bypass Through User-Controlled Key
System Score Found at
cvssv3.1 6.4
ssvc Track
Reference id Reference type URL
https://access.redhat.com/errata/RHSA-2026:30049
https://access.redhat.com/errata/RHSA-2026:30050
cpe:/a:redhat:build_keycloak:26.4::el9 Other https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:/a:redhat:build_keycloak:26.4::el9
cpe:/a:redhat:build_keycloak:26.6::el9 Other https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:/a:redhat:build_keycloak:26.6::el9
CVE-2026-9087 Advisory https://access.redhat.com/security/cve/CVE-2026-9087
RHSA-2026:25097 Advisory https://access.redhat.com/errata/RHSA-2026:25097
RHSA-2026:25098 Advisory https://access.redhat.com/errata/RHSA-2026:25098
show_bug.cgi?id=2480172 Bug https://bugzilla.redhat.com/show_bug.cgi?id=2480172
No exploits are available.

No EPSS data available for this advisory.

Patch URL
There are no known patches.
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N Found at None
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:N/A:N/T:T/P:M/B:A/M:M/D:T/2026-05-21T14:01:27Z/ Found at None

Vector: SSVCv2/E:N/A:N/T:T/P:M/B:A/M:M/D:T/2026-05-21T14:01:27Z/

Decision: Track

Source URL: https://github.com/cisagov/vulnrichment/blob/develop/2026/9xxx/CVE-2026-9087.json

Source Advisory: vulnrichment/CVE-2026-9087

View SSVC decision tree 
[{'Exploitation': 'none'},
 {'Automatable': 'no'},
 {'Technical Impact': 'total'},
 {'Mission Prevalence': 'minimal'},
 {'Public Well-being Impact': 'material'},
 {'Mission & Well-being': 'medium'}]