Low [CVE-2026-42393] Information disclosure via timing attack on `doveadm` password/API key comparison
This low-severity Red Hat Linux advisory covers CVE-2026-42393 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
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Summary
The comparison used for the doveadm password and API key is not fully timing safe and can reveal the length of the configured secret. An attacker with access to the same network as the doveadm service, able to make repeated requests and measure response timing accurately, can learn the length of the secret, which reduces the effort needed to guess it.
The secret value itself is not disclosed. Update to non-vulnerable version.
No publicly available exploits are known. A flaw was found in dovecot.
Red Hat severity: Low — CVSS 3.1 (CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N). Weakness: CWE-208.
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, restrict network access to the `doveadm` service to only trusted clients. This can be achieved by configuring firewall rules to limit inbound connections to the `doveadm` service's port from known, secure IP addresses or subnets. Consult your system's firewall documentation (e.g., `firewalld` or `iptables`) for specific configuration steps.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
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