Vulnerability · Published Sep 9, 2026 · Assigned by mitre
CVE-2026-61909
Low 3.5
In plain English
A low-severity security flaw in Cyrus IMAP from cyrusimap. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 10% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
An issue was discovered in Cyrus IMAP before 3.12.4. CalDAV/CardDAV multiget bypasses a per-href ACL. An authenticated DAV user with some shared access to another user's calendar or address book could read even unshared events or contacts by including the target hrefs in a calendar-multiget or addressbook-multiget REPORT.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | cyrus-imapd | no fix listed | DEBIAN-CVE-2026-61909 |
| Debian:13 | cyrus-imapd | no fix listed | DEBIAN-CVE-2026-61909 |
| Debian:14 | cyrus-imapd | 3.12.4-1 | DEBIAN-CVE-2026-61909 |
| Ubuntu:26.04:LTS | cyrus-imapd | no fix listed | UBUNTU-CVE-2026-61909 |
| Ubuntu:26.10 | cyrus-imapd | no fix listed | UBUNTU-CVE-2026-61909 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| cyrusimap | Cyrus IMAP | 0 – before 3.8.83.9.0 – before 3.10.43.11.0 – before 3.12.4 |
Weakness: CWE-420 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N