CVE-2026-47085 — MEDIUM (4.0)

Vulnerability Description

An issue was discovered in cyrus-imapd in Cyrus IMAP through 3.12.2. URLAUTH token forgery can occur via a missing mboxkey. If an attacker knew a folder name on the victim's account for which the victim had never issued an auth URL, they could forge a working URLAUTH token by computing an HMAC-SHA1 value with a predictable key, giving them read access to the mailbox. (URLAUTH is an obscure feature, meaning that the odds of any user actually being susceptible to this attack are very low. Perhaps no public clients use URLAUTH.)

CVSS Score

4.0

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

CHANGED

Confidentiality

LOW

Integrity

NONE

Availability

NONE

Related Weaknesses (CWE)

CWE-340

References

FAQ

What is CVE-2026-47085?

CVE-2026-47085 is a vulnerability with a CVSS score of 4.0 (MEDIUM). An issue was discovered in cyrus-imapd in Cyrus IMAP through 3.12.2. URLAUTH token forgery can occur via a missing mboxkey. If an attacker knew a folder name on the victim's account for which the vict...

How severe is CVE-2026-47085?

CVE-2026-47085 has been rated MEDIUM with a CVSS base score of 4.0/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-47085?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.