CVE-2026-18217: Improper Input Validation
Source GCVE Database
Not known to be exploited · CVSS 3.4 Low : update Red Hat build of Keycloak 26.4 when convenient.
Data as of 6 Nov 2026, 14:05 UTC
Thin evidence
One scorer or none| CNA (redhat) | CVSS 3.1 | 3.4 |
|---|
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 31 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.
What to do
Patches and advisories
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Red Hat build of Keycloak 26.4keycloak-rhel9-container | Affected– | Fixed in– |
| Red Hat build of Keycloak 26.4keycloak-rhel9-operator-bundle-container | Affected– | Fixed in– |
| Red Hat build of Keycloak 26.4keycloak-rhel9-operator-container | Affected– | Fixed in– |
| Red Hat build of Keycloak 26.6.8keycloak-services | Affected– | Fixed in– |
| Red Hat build of Keycloak 26.6.8rhbk-keycloak-rhel9/rhbk-keycloak-rhel9 | Affected– | Fixed in– |
| Red Hat build of Keycloak 26.6.8rhbk-openshift-rhel9/rhbk-openshift-rhel9 | Affected– | Fixed in– |
AI-suggested
Red Hat has released fixed images for Keycloak version 26.4.17 that address this vulnerability. Users should upgrade to these fixed versions to remediate the issue. No additional mitigation steps are indicated in the vendor advisory.
Description
A vulnerability in Keycloak's SAML protocol implementation allows an attacker to exploit the HTTP-Redirect binding when a client is configured with a wildcard redirect URL. This flaw can cause service providers to process attacker-supplied parameters instead of legitimate login data, potentially resulting in users being logged into incorrect accounts. The issue has a low CVSS score of 3.4 and does not have known exploits in the wild. Red Hat has released fixed images for Keycloak 26.4.17 addressing this and other vulnerabilities.
References
- nvd.nist.gov/vuln/detail/CVE-2026-18217 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:95760 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:95761 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-18217 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2508311 (opens in a new tab)