Auth bypass in Cyrusimap Cyrus Imap

CVE-2026-47086

An issue was discovered in cyrus-imapd in Cyrus IMAP through 3.12.2. GENURLAUTH-issued tokens can bypass ACLs. Any authenticated user could mint a URLAUTH token (via the GENURLAUTH command) for any mailbox they could name, even without read access on it. This would allow reading mail from mailboxes despite having no granted permissions.

Vulnerability class: Broken Access Control

Published · last modified .

CVSS v3 metric

CVSS v3 base score 3.5 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.003 (17.6th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 18th percentile — 17.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-47086: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-47086?
CVE-2026-47086 is a low-severity vulnerability in Cyrusimap Cyrus Imap, classified under Incorrect Authorization. CVSS score: 3.5/10. Published 2026-07-16.
How severe is CVE-2026-47086?
Low severity. CVSS v3 base score is 3.5 out of 10.