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MaddyApplication · Maddy Project

CVE-2026-40193

HIGH · 8.2 CVSS v3.1 Published 2026-04-16
Fix available
A fix is available. Upgrade to 0.9.3 or later.
See remediation →
91/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
maddy is a composable, all-in-one mail server. Versions prior to 0.9.3 contain an LDAP injection vulnerability in the auth.ldap module where user-supplied usernames are interpolated into LDAP search filters and DN strings via strings.ReplaceAll() without any LDAP filter escaping, despite the go-ldap/ldap/v3 library's ldap.EscapeFilter() function being available in the same import. This affects three code paths: the Lookup() filter, the AuthPlain() DN template, and the AuthPlain() filter. An attacker with network access to the SMTP submission or IMAP interface can inject arbitrary LDAP filter expressions through the username field in AUTH PLAIN or LOGIN commands. This enables identity spoofing by manipulating filter results to authenticate as another user, LDAP directory enumeration via wildcard filters, and blind extraction of LDAP attribute values using authentication responses as a boolean oracle or via timing side-channels between the two distinct failure paths. This issue has been fixed in version 0.9.3.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
MaddyApplication
Affected:< 0.9.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
Low
Availability
None

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

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 0.9.3 or later
Fixed in 0.9.3
Vendor patch github.com →
Recommended fix High confidence

0.9.3

  1. 1. Check the currently installed Maddy version using your package manager or by running `maddy --version`
  2. 2. Create a backup of your Maddy configuration directory (typically /etc/maddy or /etc/maddy's config path)
  3. 3. Upgrade Maddy to version 0.9.3 using your system's package manager or by downloading from the official releases (e.g., `apt update && apt install maddy` or `yum update maddy`, or manual binary replacement)
  4. 4. Verify the upgrade was successful by running `maddy --version` and confirming it shows 0.9.3 or higher
  5. 5. Restart the Maddy service to load the updated version (e.g., `systemctl restart maddy` or `service maddy restart`)
  6. 6. Test authentication via SMTP/IMAP to confirm the LDAP injection vulnerability is resolved

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-40193 in production — separate from our analysis above.

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What belongs here
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  • Version or environment caveats, and links to real fixes
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