# CVE-2026-42393: Information disclosure in OX Dovecot CE

> An attacker on the same network can measure response timing to reveal the length of the doveadm secret, aiding brute-force attacks.

- **Severity:** Low 3.1 (`CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Aug 2026
- **Updated:** 28 Aug 2026
- **Also known as:** ALPINE-CVE-2026-42393, AZL-98310, DEBIAN-CVE-2026-42393, GHSA-j4gv-hpmc-xf3m, UBUNTU-CVE-2026-42393

## What is CVE-2026-42393?

CVE-2026-42393 is a low-severity vulnerability in Open-Xchange GmbH OX Dovecot CE, published on 28 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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.

Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2026-42393?


## How do I fix CVE-2026-42393?

Upgrade to a fixed version.

## Is CVE-2026-42393 being exploited?

There is no known exploitation of CVE-2026-42393 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42393 and fix it if it is affected.

What it is: CVE-2026-42393 is a low-severity vulnerability in Open-Xchange GmbH OX Dovecot CE, published on 28 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-42393 in the wild and no public exploit code.

Affected product: Open-Xchange GmbH OX Dovecot CE. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-42393/ (Markdown: https://insights.sbomify.com/CVE-2026-42393/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42393
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42393
- OSV: https://osv.dev/vulnerability/CVE-2026-42393

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42393/
Summaries are generated and may contain mistakes; the official description above is the record.