CVE-2026-40606

Description

mitmproxy is a interactive TLS-capable intercepting HTTP proxy for penetration testers and software developers and mitmweb is a web-based interface for mitmproxy. In mitmproxy 12.2.1 and below, the builtin LDAP proxy authentication does not correctly sanitize the username when querying the LDAP server. This allows a malicious client to bypass authentication. Only mitmproxy instances using the proxyauth option with LDAP are affected. This option is not enabled by default. The vulnerability has been fixed in mitmproxy 12.2.2 and above.

How to fix CVE-2026-40606

To remediate CVE-2026-40606, upgrade the affected package to a fixed version below.

• —no fix listed
• —upgrade to 12.2.2 or later
• —upgrade to 12.2.2 or later

Is CVE-2026-40606 being exploited?

Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.

Affected packages (3)

• from 0
• from 0, < 12.2.2
• from 0, < 12.2.2

CVSS scores

References (5)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2026-40606
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2026-40606
• PATCHgithub.com/mitmproxy/mitmproxy
• WEBgithub.com/mitmproxy/mitmproxy/security/advisories/GHSA-527g-3w9m-29hv