What’s Vulnerable › Vulnerabilities

CVE-2023-27582: Full authentication bypass if SASL authorization username is specified

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-03-13 · updated 2026-06-17
• Weakness: CWE-287

Description

maddy is a composable, all-in-one mail server. Starting with version 0.2.0 and prior to version 0.6.3, maddy allows a full authentication bypass if SASL authorization username is specified when using the PLAIN authentication mechanisms. Instead of validating the specified username, it is accepted as is after checking the credentials for the authentication username. maddy 0.6.3 includes the fix for the bug. There are no known workarounds.

Affected products

• foxcpp maddy: from 0.2.0 before 0.6.3 — fixed in 0.6.3

How to fix

Upgrade to a fixed version: foxcpp maddy 0.6.3. Check the vendor advisory for mitigations.

References

• https://github.com/foxcpp/maddy/commit/55a91a37b71210f34f98f4d327c30308fe24399a
• https://github.com/foxcpp/maddy/commit/9f58cb64b39cdc01928ec463bdb198c4c2313a9c
• https://github.com/foxcpp/maddy/releases/tag/v0.6.3
• https://github.com/foxcpp/maddy/security/advisories/GHSA-4g76-w3xw-2x6w
• https://github.com/foxcpp/maddy/commit/55a91a37b71210f34f98f4d327c30308fe24399a
• https://github.com/foxcpp/maddy/commit/9f58cb64b39cdc01928ec463bdb198c4c2313a9c
• https://github.com/foxcpp/maddy/releases/tag/v0.6.3
• https://github.com/foxcpp/maddy/security/advisories/GHSA-4g76-w3xw-2x6w

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