SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

CVE-2026-42008

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.

MEDIUM 4.3EPSS 0.24%

Does this matter?

Lower severity and a low EPSS score (0.24%). Track it; it rarely justifies an emergency change on its own.

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 3.1
4.3 MEDIUMCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS
0.24% probability · 14th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-287
Source
security@open-xchange.com
EPSS trend
0%3%5%26 October 2026: 0.24%26 October 202626 October 2026

EPSS 0.2% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.