An issue was discovered in cyrus-imapd in Cyrus IMAP through 3.12.2. (CVE-2026-47086)
Description
Cyrus IMAP through version 3.12.2 contains a vulnerability where authenticated users can generate URLAUTH tokens for any mailbox, bypassing access control lists (ACLs). This allows unauthorized reading of mailboxes without granted permissions. The issue affects multiple specific versions of cyrus-imapd. The CVSS score is 3.5, indicating medium severity.
CVSS v3.1
Score 3.5low
Affected software
pkg:deb/ubuntu/cyrus-imapd?arch=source&distro=esm-apps/bionicpkg:deb/ubuntu/cyrus-imapd?arch=source&distro=esm-apps/focalpkg:deb/ubuntu/cyrus-imapd?arch=source&distro=esm-apps/jammypkg:deb/ubuntu/cyrus-imapd?arch=source&distro=esm-apps/noblepkg:deb/ubuntu/cyrus-imapd?arch=source&distro=stonkingpkg:deb/ubuntu/cyrus-imapd?arch=source&distro=resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
An issue in cyrus-imapd (Cyrus IMAP) through version 3.12.2 allows any authenticated user to mint a URLAUTH token via the GENURLAUTH command for any mailbox they can name, regardless of read access permissions. This token bypasses ACLs, enabling unauthorized reading of mailbox contents. The vulnerability affects numerous specific package versions across multiple releases. The CVSS 3.1 vector indicates network attack vector, high attack complexity, low privileges required, no user interaction, scope changed, and low confidentiality impact.
Potential Impact
Any authenticated user can bypass mailbox ACLs by generating URLAUTH tokens for mailboxes they do not have permission to read, potentially exposing mailbox contents without authorization. There is no indication of integrity or availability impact. The confidentiality impact is rated low.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch links are provided in the available data. Until a patch is available, restrict authenticated user permissions where possible and monitor for unusual GENURLAUTH command usage.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-47086
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:Pro:18.04:LTS","Ubuntu:Pro:20.04:LTS","Ubuntu:Pro:22.04:LTS","Ubuntu:Pro:24.04:LTS","Ubuntu:26.10","Ubuntu:26.04:LTS"]
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ad3f64c2cdf04f656665859
Added to database: 10/17/2026, 22:27:24 UTC
Last enriched: 10/18/2026, 01:23:29 UTC
Last updated: 10/18/2026, 01:23:29 UTC
Views: 3
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