CVE-2026-42008 — MEDIUM (4.3)

Vulnerability Description

Forwarding information received from a host listed as a trusted proxy is not kept separate from Dovecot's own authentication fields, so a value sent by that host can be injected as an internal authentication field. Any host permitted to act as a trusted proxy can authenticate as any user without knowing that user's password. This affects deployments whose password database honours a field that permits authentication without a password. Deployments that do not configure trusted proxies are not affected. Restrict the list of trusted proxy networks to hosts that are fully under your control. Update to non-vulnerable version. No publicly available exploits are known.

CVSS Score

4.3

MEDIUM

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

Attack Vector

ADJACENT_NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

NONE

Integrity

LOW

Availability

NONE

Related Weaknesses (CWE)

CWE-287

References

https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxd

FAQ

What is CVE-2026-42008?

CVE-2026-42008 is a vulnerability with a CVSS score of 4.3 (MEDIUM). Forwarding information received from a host listed as a trusted proxy is not kept separate from Dovecot's own authentication fields, so a value sent by that host can be injected as an internal authent...

How severe is CVE-2026-42008?

CVE-2026-42008 has been rated MEDIUM with a CVSS base score of 4.3/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-42008?

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