4.3

CVE-2026-42008: open-xchange gmbh ox dovecot ce Improper Authentication

CVSS: 4.3v3.1MediumDeferred
AliasesUBUNTU-CVE-2026-42008DEBIAN-CVE-2026-42008
Published 28-08-2026Last modified 28-08-2026
Open JSON

Vulnerability summary

CVE-2026-42008 is a medium (CVSS 4.3) Improper Authentication vulnerability in open-xchange gmbh ox dovecot ce. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 13.7% of scored vulnerabilities.

Overall risk
17/100
0100
Low · default modelHow is this calculated?
CVSS score
4.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.24%
0%100%
Low · +0.04 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 4 · Related 3
MGASA-2026-0385OPENSUSE-SU-2026:21720-1SUSE-SU-2026:23595-1SUSE-SU-2026:4139-1

Timeline

  1. 28-08-2026
    PublishedVulnerability first disclosed.
  2. 28-08-2026
    Last modifiedVulnerability information updated.

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 metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.24%

Chance of exploitation in the next 30 days

Percentile

14%

Versus all other CVEs

30-day change

+0.04 pp

From 0.19% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.24%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Open-xchange gmbh2 products
Debian1 product
  • dovecotAll versions (No fix recorded) | < 1:2.4.1+dfsg1-6+deb13u7 | < 1:2.4.5+dfsg1-1
Ubuntu1 product
  • dovecotAll versions (No fix recorded)

3 vendors · 4 products

References

4 links