NVD / CVE Program· CNA OX

CVE-2026-42393: The comparison used for the doveadm password and API key is not fully timing safe and can reveal the length of the configured secret.

Noroxi assessment

Priority: Monitor (action score 12/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.17% (FIRST EPSS).
Someone on the same network segment can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
Fixed version: Open-Xchange GmbH OX Dovecot CE 2.4.5; Open-Xchange GmbH OX Dovecot Pro 2.3.22.2, 3.0.7, 3.1.6.

Low priority for now. Upgrade to Open-Xchange GmbH OX Dovecot CE 2.4.5; Open-Xchange GmbH OX Dovecot Pro 2.3.22.2, 3.0.7, 3.1.6 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

LowCVSS 3.1 · v3.1—No exploit Fix available

Published: Aug 28, 2026
Updated: Sep 3, 2026
EPSS: 0.1% · 6th percentile
CWE: CWE-200

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 12 / 40 · 3.1 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · OX: 3.1; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (OX). Independent of NVD's CPE analysis and usually ahead of it.

Open-Xchange GmbH OX Dovecot CE
- 2.3.0 and later · before 2.4.5affected · semver
Open-Xchange GmbH OX Dovecot Pro
- 2.3.0 and later · before 2.3.22.2affected · semver
- 3.0.0 and later · before 3.0.7affected · semver
- 3.1.0 and later · before 3.1.6affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Alpine:v3.23	dovecot	before 2.4.5-r0	2.4.5-r0
Debian:12	dovecot	from 0	—
Debian:13	dovecot	before 1:2.4.1+dfsg1-6+deb13u7	1:2.4.1+dfsg1-6+deb13u7
Debian:14	dovecot	before 1:2.4.5+dfsg1-1	1:2.4.5+dfsg1-1
openSUSE:Leap 16.0	dovecot24	before 2.4.4-160000.2.1	2.4.4-160000.2.1
openSUSE:Tumbleweed	dovecot24	before 2.4.5-1.1	2.4.5-1.1
SUSE:Linux Enterprise Server 12 SP5-LTSS	dovecot22	before 2.2.31-19.40.1	2.2.31-19.40.1
SUSE:Linux Enterprise Server 16.0	dovecot24	before 2.4.4-160000.2.1	2.4.4-160000.2.1

Same product

open-xchange gmbh: all records

Other highest-scoring records for the same primary product.

CVE-2026-42007An attacker that has valid credentials can use a Sieve script with the editheader extension to trigger a use-after-free in the mail editing
36Monitor
CVE-2026-42391An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CP
30Monitor
CVE-2026-33605An unauthenticated attacker can crash the ManageSieve login process by sending a small malformed command before authenticating.
30Monitor

Published before and after this one in the same product

← EarlierCVE-2026-42008Aug 28, 2026 · Forwarding information received from a host listed as a trusted proxy is not kept separate from Dovecot's own authentication fields, so a va
17Monitor
← EarlierCVE-2026-42392Aug 28, 2026 · An attacker that has valid credentials can send an invalid IMAP URLFETCH command, which causes uninitialized memory to be included in the er
17Monitor
Later →CVE-2026-42395Aug 28, 2026 · A host listed as a trusted proxy can send forwarding information containing a NUL byte, which crashes the login process on the following log
17Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Open-Xchange GmbH OX Dovecot CE	2.4.5	Vendor (CNA)
Open-Xchange GmbH OX Dovecot Pro	2.3.22.2	Vendor (CNA)
Open-Xchange GmbH OX Dovecot Pro	3.0.7	Vendor (CNA)
Open-Xchange GmbH OX Dovecot Pro	3.1.6	Vendor (CNA)
alpine:dovecot	2.4.5-r0 · Alpine:v3.23	Package registry (OSV)
debian:dovecot	1:2.4.1+dfsg1-6+deb13u7 · Debian:13	Package registry (OSV)
opensuse:dovecot24	2.4.5-1.1 · openSUSE:Tumbleweed	Package registry (OSV)
suse:dovecot22	2.2.31-19.40.1 · SUSE:Linux Enterprise Server 12 SP5-LTSS	Package registry (OSV)
suse:dovecot24	2.4.4-160000.2.1 · SUSE:Linux Enterprise Server 16.0	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

CVE-2026-423920 days apartAn attacker that has valid credentials can send an invalid IMAP URLFETCH command, which causes uninitialized memory to be included in the er
17Monitor
CVE-2026-402030 days apartWhen IMAP compression is enabled, the same compression state is reused across responses in a session, so response sizes depend on both attac
14Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Someone on the same network segment can trigger it.
No account or password is required.
No user action is required.
Special conditions such as timing or configuration are required.

If successful

Confidentiality: low · data can be read
Integrity: none
Availability: none

Attack vector: Adjacent
Attack complexity: High
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: Low
Integrity impact: None
Availability impact: None

Weakness class (CWE)

CWE-200 · Exposure of Sensitive Information to an Unauthorized Actor

CVSS vector

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

nvd-secondary

Root cause

The extension requests broader permissions than its function needs and sends the data it collects out for purposes beyond its stated function.

The bug in code

The whole CWE-200 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

json

1{
2  "permissions": ["tabs", "<all_urls>"],
3  "background": { "service_worker": "analytics.js" }
4}

Fixed

json

1{
2  "permissions": ["activeTab"],
3  "host_permissions": ["https://yildiz.example/*"]
4}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Change log

Fix✗ → ✓Sep 28, 2026, 10:08 PM UTC

For records you follow, these changes also arrive as notifications. →

References

documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0003.json

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records