Medium [CVE-2026-47085] Information disclosure via URLAUTH token forgery
This medium-severity Red Hat Linux advisory covers CVE-2026-47085 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
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Summary
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.) A remote attacker could exploit a vulnerability related to URLAUTH token forgery, caused by a missing mailbox key. The likelihood of exploitation is low due to the obscurity of the URLAUTH feature.
Red Hat severity: Moderate — CVSS 4 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N). Weakness: CWE-341.
Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9. Will not fix / out of support: Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7.
Red Hat does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: cyrus-imapd.
- 3.12.2
Official advisory · high-confidence parse· fetched 5 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 5 days ago·verify at source
Mitigation checklist
- 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.
Official advisory · high-confidence parse· fetched 5 days ago·verify at source
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