VulnerabilityPublished 14 Sep 2026

CVE-2026-56668: ZITADEL · Unauthorized Token Privilege Escalation in OAuth2 Token Exchange

Affects github.com/zitadel/zitadelSource GCVE Database

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Not known to be exploited · CVSS 8.1 High : upgrade to 4.15.3 soon.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

8.1High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 35% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.15.3

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 14 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade github.com/zitadel/zitadel to 4.15.3.

Affected software

Product	Affected	Fixed in
Gogithub.com/zitadel/zitadel	Affected <4.15.3	Fixed in 4.15.3

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available in ZITADEL version 4.15.3 and later; upgrading to these versions is the recommended remediation. If immediate upgrade is not possible, mitigate by disabling the Token Exchange feature flag (ZITADEL_DEFAULTINSTANCE_FEATURES_TOKENEXCHANGE=false) in versions prior to 4.11.0, or by removing the Token Exchange grant type from all configured applications, especially high-privilege or public clients. These mitigations prevent exploitation by disabling or restricting the vulnerable functionality.

Description

A vulnerability in ZITADEL's OAuth2 Token Exchange endpoint allows an authenticated user or client to escalate privileges by exchanging a low-privilege token for a token with elevated permissions in a different application. This occurs due to missing verification of token ownership and scope restrictions during the token exchange process. The flaw affects ZITADEL versions 3.0.0 through 3.4.12 and 4.0.0 through 4.15.2. The issue has been fixed in versions 4.15.3 and later. Mitigations include upgrading to a patched version, disabling the Token Exchange feature flag, or removing the token exchange grant type from applications.

Impact

An attacker with access to a low-privilege token can exploit this vulnerability to escalate privileges by obtaining tokens with administrative roles or access to sensitive data in other applications within the system. This bypasses configured client permissions, project roles, and scope restrictions, potentially leading to unauthorized access and data exposure. The risk is higher for public clients that do not require client authentication.

Summary

ZITADEL's OAuth2 Token Exchange endpoint (grant type urn:ietf:params:oauth:grant-type:token-exchange) lacks proper validation to ensure that the incoming access token belongs to or is authorized for the client requesting the exchange. Additionally, it does not enforce that the requested scopes during token exchange remain within the original token's scopes. This allows an attacker with a low-privilege token to obtain a token with elevated permissions for a different, more privileged application, bypassing intended authorization and separation policies. Public clients without client secrets increase the risk. The vulnerability affects versions 3.0.0 through 3.4.12 and 4.0.0 through 4.15.2. The issue is resolved in version 4.15.3 by enforcing strict audience ownership verification and scope restrictions during token exchange.

CWE-862Missing Authorization (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #4OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product does not perform an authorization check when an actor attempts to access a resource or perform an action.
Architecture and Design
Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries.
Architecture and Design
Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.8 (opens in a new tab)
V13.4.2 (opens in a new tab)
V7.2.2 (opens in a new tab)
Attack patterns
Exploitation of Thunderbolt Protection Flaws (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 15 Sep 2026, 02:06 UTC

WeaknessesCWE-862

Technical details

References

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