PatchSiren cyber security CVE debrief
CVE-2026-55671 zitadel CVE debrief
A vulnerability was found in ZITADEL, an open-source identity management platform, affecting versions from 4.0.0-rc.1 through 4.15.1. The issue lies in the inconsistent validation of user-defined URLs against protected denylist handling in HTTP notification channels, OIDC BackChannel Logout, and SAML metadata URL fetches. This allows server-side requests to loopback, internal IP, link-local, or redirected endpoints through DNS rebinding, redirects, or protocol downgrades. The vulnerability is fixed in version 4.15.2. Users should review and validate affected scope and vendor guidance.
- Vendor
- zitadel
- Product
- Unknown
- CVSS
- LOW 2.3
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-07-10
- Original CVE updated
- 2026-07-10
- Advisory published
- 2026-07-10
- Advisory updated
- 2026-07-10
Who should care
Users of ZITADEL identity management platform versions 4.0.0-rc.1 through 4.15.1 should be aware of this vulnerability and take necessary actions to protect their systems. Operators, platform administrators, vulnerability management teams, and security teams should review and validate affected scope and vendor guidance.
Technical summary
The vulnerability in ZITADEL's HTTP notification channels, OIDC BackChannel Logout, and SAML metadata URL fetches allows server-side requests to loopback, internal IP, link-local, or redirected endpoints through DNS rebinding, redirects, or protocol downgrades. This issue is due to inconsistent validation of user-defined URLs against protected denylist handling. Affected product deployments should be reviewed for exposure.
Defensive priority
Medium
Recommended defensive actions
- Update ZITADEL to version 4.15.2 or later
- Review and validate user-defined URLs against protected denylist handling
- Implement additional security measures to prevent server-side requests to loopback, internal IP, link-local, or redirected endpoints
- Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
- Review compensating controls for exposed systems while remediation is scheduled and verified
- Check relevant monitoring, detection, and logs for exposed assets that need extra review
- Track exceptions, retest remediated assets, and close the item only after evidence is documented
Evidence notes
The CVE record was published on 2026-07-10T18:16:23.503Z and was last modified on 2026-07-10T18:56:43.823Z. The NVD entry is currently Deferred. Evidence is limited to CVE and NVD information. Defenders should verify affected scope and vendor guidance.
Official resources
AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-10T18:16:23.503Z and has not been modified since then. The NVD entry is currently Deferred.