Medium [CVE-2026-42392] Information disclosure via invalid IMAP URLFETCH command
This medium-severity Red Hat Linux advisory covers CVE-2026-42392 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
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Summary
An attacker that has valid credentials can send an invalid IMAP URLFETCH command, which causes uninitialized memory to be included in the error response returned to the client. Process memory contents can be disclosed to the client, which may include sensitive data.
Disable the IMAP URLAUTH functionality. Update to non-vulnerable version.
No publicly available exploits are known. A flaw was found in Dovecot.
Red Hat severity: Moderate — CVSS 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N). Weakness: CWE-908.
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 does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: dovecot.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 1 hour 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 1 hour ago·verify at source
Mitigation checklist
- To mitigate this issue, disable the IMAP URLAUTH functionality in Dovecot. This can typically be achieved by commenting out or removing the `mail_plugins = $mail_plugins imap_urlauth` line from your Dovecot configuration file (e.g., `/etc/dovecot/conf.d/20-imap.conf` or similar). A restart of the Dovecot service is required for the changes to take effect, which may temporarily interrupt mail services.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
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