CVE-2026-40020
Description
A flaw was found in dovecot. A remote attacker can exploit the Internet Message Access Protocol (IMAP) SETACL command to inject "anyone" permissions into a user's dovecot-acl file, even when the imap_acl_allow_anyone setting is disabled. This vulnerability allows an attacker to spam folders to all users, leading to a denial of service by disrupting normal email service. No unauthorized access to user data is gained.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
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 | 6.5 | 4.3 | 3.1 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | Low | Low | High |
| Privileges Required | Low | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | None | None |
| Integrity Impact | None | None | None |
| Availability Impact | High | Low | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
cve.org: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
Understanding the Weakness (CWE)
Confidentiality,Integrity,Availability,Other
Technical Impact: Execute Unauthorized Code or Commands; Alter Execution Logic; Read Application Data; Modify Application Data
An attacker could include arguments that allow unintended commands or code to be executed, allow sensitive data to be read or modified or could cause other unintended behavior.
Frequently Asked Questions
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