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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
2026-07-14
Advisory published
2026-07-10
Advisory updated
2026-07-14

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.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-55671 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-55671

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-55671 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-55671

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.