CVE-2026-40606: mitmproxy is a interactive TLS-capable intercepting HTTP proxy for penetration testers and software developers

Q: How do I fix CVE-2026-40606?

mitmproxy: upgrade to 12.2.2. Exact commands for each OS are on this page.

Q: Is CVE-2026-40606 being exploited?

CVE-2026-40606 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-40606 affect?

CVE-2026-40606 affects mitmproxy. Severity is medium (CVSS 4.8). 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

Q: How urgent is CVE-2026-40606?

Priority 23/100. Remotely exploitable, no login, no user action

Routine

MEDIUM 4.8REMOTEUPGRADE

CVE-2026-40606 is a medium-severity flaw (CVSS 4.8) affecting mitmproxy. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 i

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	4.8 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 94%)
CISA exploited list	No
Weakness	CWE-90
Published	2026-04-21
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: mitmproxy

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-21 18:16 UTCPublished CVE record published
2026-06-17 10:45 UTCUpdated Record last modified

mitmproxy mitmproxy UPGRADE

Affected: < 12.2.2

Fixed in: 12.2.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy mitmproxy || rpm -q mitmproxy || mitmproxy --version

2. UPGRADE to 12.2.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade mitmproxy

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade mitmproxy

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-40606?

mitmproxy: upgrade to 12.2.2. Exact commands for each OS are on this page.

Is CVE-2026-40606 being exploited?

CVE-2026-40606 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-40606 affect?

CVE-2026-40606 affects mitmproxy. Severity is medium (CVSS 4.8). 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

How urgent is CVE-2026-40606?

Priority 23/100. Remotely exploitable, no login, no user action

References

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