CVE-2026-55672Network attack vector

Cross-client token exchange via missing client binding

Published Jul 10, 2026 · Updated Jul 10, 2026

Improper authorization in ZITADEL before 3.4.12 and 4.0.0-rc.1 through 4.15.1 allows remote attackers to exchange intercepted OAuth grants. The OAuth2 and OIDC CodeExchange, RefreshToken, and device-token handlers validate grant format and expiration but do not compare the requesting client_id with the client bound to the original grant. Exploitation requires prior interception of a code, refresh token, or device grant; PKCE limits code injection but not cross-client refresh-token use, which grants unauthorized persistent access.

CVSS severity7.4
High
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper authorization in ZITADEL before 3.4.12 and 4.0.0-rc.1 through 4.15.1 allows remote attackers to exchange intercepted OAuth grants. The OAuth2 and OIDC CodeExchange, RefreshToken, and device-token handlers validate grant format and expiration but do not compare the requesting client_id with the client bound to the original grant. Exploitation requires prior interception of a code, refresh token, or device grant; PKCE limits code injection but not cross-client refresh-token use, which grants unauthorized persistent access.

The record

CVE
CVE-2026-55672
Published
Jul 10, 2026
Updated
Jul 10, 2026
Vendor
ZITADEL
Product
ZITADEL
Classifications
CWE-287, CWE-863, T1550.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.4.12
  2. Affected versionversion=>= 4.0.0-rc.1, < 4.15.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ZITADEL · ZITADELversion=< 3.4.12; version=>= 4.0.0-rc.1, < 4.15.2

Published CVSS scores

7.4GitHub Maintainer AdvisoryCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
CWE-863Incorrect Authorization
T1550.001Application Access Token

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo