CVE-2026-73208
Description
A flaw was found in Dovecot. This vulnerability allows an attacker to bypass authentication by exploiting how OAuth2 tokens are validated. If an OAuth2 token response does not include a scope claim, Dovecot incorrectly uses the audience claim in its place for authorization checks. This can lead to unauthorized access, as a token with no relevant permissions might be accepted if its intended recipient value matches a configured scope name.
Mitigation
To mitigate this issue, ensure that the identity provider issues a scope claim for all tokens used with Dovecot. Additionally, verify that configured scope names in Dovecot do not match audience values from the identity provider. A restart of the Dovecot service may be required for configuration changes to take effect.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.4 | N/A | 7.4 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Understanding the Weakness (CWE)
Access Control
Technical Impact: Bypass Protection Mechanism
Frequently Asked Questions
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