CVE-2026-55670

LOWPre-NVD 0.0
0.0
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • No confirmed exploitation signals yet
CISA-KEV: Not listedEPSS: —CVSS: —Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

ZITADEL: Cross-Tenant User Leakage via Recycled Identifiers

Summary

A flaw in the user lifecycle enforcement allowed deleted users to retain their original organization/tenant association. Recreating a deleted user under a distinct organization can cause the new user instance to be incorrectly provisioned within the original organization if the previous ID would be used to recreate it.

Impact

When a user is created, the system maps the generated or provided ID to its target organization (Org A). When that user is subsequently deleted, a deletion event is appended to the stream, but the historical mapping of the resource owner within the event store's validation layer is not cleared.

If a new user is later provisioned in a different organization (Org B) using that exact same ID, the event store validation logic reads the stream's history, matches it to the original organization, and routes the new user's events to Org A instead of Org B.

This issue represents a localized multi-tenancy isolation anomaly rather than an easily exploitable attack vector. Because the new user instance is incorrectly routed and provisioned inside Org A instead of Org B, an administrator from Org A inadvertently gains full access to this new user record.

However, there is no technical mechanism for a malicious actor to force, automate, or target this behavior against a specific user or tenant. Because the scenario relies entirely on an accidental sequence of operational events and requires the recycling of a highly specific ID space, the practical security risk is exceptionally low.

Affected Versions

Systems running one of the following versions are affected:

* 4.x: 4.0.0 through 4.15.1 (including RC versions) * 3.x: 3.0.0 through 3.4.11 (including RC versions)

Patches

The vulnerability has been addressed in the latest releases. The patch resolves the issue by requiring the correct permission in case the verification flag is provided and only allows self-management of the email address, resp. phone number itself.

Workarounds

The recommended solution is to upgrade to a patched version.

Questions

If you have any questions or comments about this advisory, please email us at [email protected]

Credits

Thanks to Charlie Graven from Famedly for reporting this vulnerability.

CVSS v3
—
EG Score
0.0(none)
EPSS
—
KEV
Not listed

Published

June 18, 2026

Last Modified

June 18, 2026

Vendor Advisories for CVE-2026-55670(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFixed inDependents
github.com/zitadel/zitadel—1.80.0-v2.20.0.20260615092437-6082e59d47c1—

Data Freshness Timeline

(refreshed 0× in last 7d / 1× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-06-18 13:45 UTCEG score recompute

Frequently asked(3)

What is CVE-2026-55670?
CVE-2026-55670 is a low vulnerability published on June 18, 2026. ZITADEL: Cross-Tenant User Leakage via Recycled Identifiers Summary A flaw in the user lifecycle enforcement allowed deleted users to retain their original organization/tenant association. Recreating a deleted user under a distinct organization can cause the new user instance to be incorrectly…
When was CVE-2026-55670 disclosed?
CVE-2026-55670 was first published in the National Vulnerability Database on June 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
How do I remediate CVE-2026-55670?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55670, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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