CVE-2026-42393: Infoleak
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. Restrict network access to the doveadm service to trusted clients. Update to non-vulnerable version. No publicly available exploits are known.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/dovecotto a version that resolves this vulnerability.Fixed in 1:2.3.19.1+dfsg1-2.1+deb12u7 - Upgrade
Upgrade
debian/dovecotto a version that resolves this vulnerability.Fixed in 1:2.4.1+dfsg1-6+deb13u7 - Upgrade
Upgrade
debian/dovecotto a version that resolves this vulnerability.Fixed in 1:2.4.5+dfsg1-1 - Upgrade
Upgrade
debian/dovecotto a version that resolves this vulnerability.Fixed in 1:2.3.19.1+dfsg1-2.1+deb12u7Fixed in 1:2.4.1+dfsg1-6+deb13u7Fixed in 1:2.4.5+dfsg1-4 - Compensating control
Restrict network access to the doveadm service to trusted clients.
- Operational
Update to non-vulnerable version.
Event History
Frequently Asked Questions
Who is realistically exposed to this issue?
Deployments where the doveadm service is reachable by untrusted systems on the same network are exposed. An attacker must be able to send repeated requests and measure response timing accurately.
What can an attacker learn from the timing behavior?
The timing difference can reveal the length of the configured doveadm password or API key. It does not disclose the secret value itself, but knowing its length reduces the effort required to guess it.
Are credentials or user interaction required to exploit this?
No privileges or user interaction are required, but the attacker needs network access to the doveadm service and the ability to perform repeated, accurate timing measurements.
What should be done if an update cannot be applied immediately?
Restrict network access to the doveadm service so that only trusted clients can reach it. This limits the ability of an attacker to make the repeated requests needed for timing analysis.
Are public exploits available?
No publicly available exploits are known.