CVE-2026-4366
Keycloak-services: blind server-side request forgery (ssrf) via http redirect handling in keycloak
- 5.8MediumCVSS base score
- 0.24%Exploitation in 30 daysEPSS · top 85% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
A flaw was identified in Keycloak, an identity and access management solution, where it improperly follows HTTP redirects when processing certain client configuration requests. This behavior allows an attacker to trick the server into making unintended requests to internal or restricted resources. As a result, sensitive internal services such as cloud metadata endpoints could be accessed. This issue may lead to information disclosure and enable attackers to map internal network infrastructure.
Timeline
ID reserved
By redhat
Published
- 3 months later
· 3 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| redhatCNA (assigner) | 3.1 | Medium5.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N |
| NVDNVD · Modified | 3.1 | Medium5.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N |
- EPSS (exploitation in 30 days)
- 0.24% · top 85% of all CVEs (9 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.8.
Affected products
Red Hat · Red Hat build of Keycloak 26.4
- unaffected 26.4.12-1 – < *
Red Hat · Red Hat build of Keycloak 26.4
- unaffected 26.4-17 – < *
Red Hat · Red Hat build of Keycloak 26.4
- unaffected 26.4-17 – < *
Red Hat · Red Hat build of Keycloak 26.4.12
All versions: unaffected
Red Hat · Red Hat Build of Keycloak
All versions: affected
Red Hat · Red Hat Build of Keycloak
All versions: affected
Red Hat · Red Hat JBoss Enterprise Application Platform 8
All versions: affected
Red Hat · Red Hat JBoss Enterprise Application Platform Expansion Pack
All versions: affected
Red Hat · Red Hat Single Sign-On 7
All versions: affected
What to do
Workaround: To mitigate this vulnerability, restrict the outbound network access of the Keycloak instance. Configure firewall rules to prevent the Keycloak server from initiating connections to internal network segments, especially to well-known cloud metadata service IP addresses such as `169.254.169.254`. For example, on Red Hat Enterprise Linux, you can use `firewalld` to add a rich rule: `sudo firewall-cmd --permanent --zone=public --add-rich-rule='rule family="ipv4" destination address="169.254.169.254" reject'` `sudo firewall-cmd --reload` This may impact other services if they legitimately rely on accessing these internal IPs. Additionally, ensure that any configured `sector_identifier_uri` values are thoroughly validated to only point to trusted, external URLs that do not perform redirects to internal resources.
References
4
- RHSA-2026:19596 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
- RHSA-2026:19597 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2026-4366 (opens in a new tab)vdb-entryx_refsource_REDHAT
- RHBZ#2448543 (opens in a new tab)issue-trackingx_refsource_REDHAT
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-12762 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-4366)Record last updated .