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CVE-2026-40193

Maddy vulnerability

8.2 HIGHPublic exploitEPSS 0.52%
  1. Published15 Apr 2026

Description

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityLow
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

Affected products

Maddy< 0.9.3

Remediation

Fixed in
Maddy≥ 0.9.3

References

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Frequently asked

Is CVE-2026-40193 being actively exploited?

CVE-2026-40193 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.52%.

How severe is CVE-2026-40193?

CVE-2026-40193 has a CVSS 3.1 base score of 8.2, rated high. EPSS estimates a 0.52% probability of exploitation.

Which products are affected by CVE-2026-40193?

Affected products include Maddy.

How do I fix CVE-2026-40193?

Upgrade affected software to a fixed version, for example Maddy 0.9.3 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-40193 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.