CVE-2026-44305 is a medium-severity security vulnerability in lemur (pip), affecting versions < 1.9.0. It is fixed in 1.9.0.
Description Overview When LDAP TLS is enabled (LDAPUSETLS = True), Lemur's LDAP authentication module unconditionally disables TLS certificate verification at the global ldap module level. This allows a man-in-the-middle attacker positioned between Lemur and the LDAP server to intercept all authentication credentials. Vulnerable Code Location: lemur/auth/ldap.py, bind() method, line ~172 Key issues: ldap.setoption() is a global call (as opposed to self.ldapclient.setoption()), meaning it disables TLS verification for the entire Python process, not just this connection OPTXTLSNEVER means no certificate validation is performed whatsoever, self-signed, expired, wrong hostname, and revoked certificates are all silently accepted There is no configuration option to override this behavior, TLS verification is always disabled when TLS is enabled Impact A network-positioned attacker (man-in-the-middle) between Lemur and the LDAP server can: Intercept all LDAP credentials (usernames and plaintext passwords) for every user who authenticates Modify LDAP responses to inject arbitrary group memberships, granting admin access Compromise the entire PKI infrastructure managed by Lemur, since authentication controls access to certificates and private keys This is particularly severe because Lemur is a certificate management system, the tool designed to manage TLS security is itself vulnerable to a TLS attack. Steps to Reproduce Deploy Lemur with LDAP TLS enabled: python LDAPAUTH = True LDAPUSETLS = True LDAPBINDURI = "ldaps://dc.corp.example.com" Intercept the LDAP connection using a TLS proxy (e.g., mitmproxy or stunnel): bash # Generate a self-signed certificate openssl req -x509 -newkey rsa:2048 -keyout mitm.key -out mitm.crt -days 1 -nodes -subj "/CN=mitm" # Proxy LDAP traffic stunnel -d 0.0.0.0:636 -r real-ldap-server:636 -p mitm.pem Point Lemur's LDAPBINDURI at the proxy (or perform ARP spoofing/DNS hijacking) Observe that Lemur connects without any certificate verification error All credentials are visible in the proxy's TLS session Remediation Remove the global TLS verification bypass and default to strict verification: If backward compatibility is needed, make it configurable with a secure default: Resources CWE-295: https://cwe.mitre.org/data/definitions/295.html python-ldap TLS documentation: https://www.python-ldap.org/en/python-ldap-3.4.0/reference/ldap.html#tls-options
CVE-2026-44305 has a CVSS score of 6.8 (Medium). The vector is reachable from an adjacent network, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.
A fixed version is available (1.9.0). Upgrading removes the vulnerable code path.
pip
lemur (< 1.9.0)lemur → 1.9.0 (pip)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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Already deployed Kodem? See CVE-2026-44305 in your environment →Upgrade lemur to 1.9.0 or later to resolve this vulnerability.
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CVE-2026-44305 is a medium-severity security vulnerability in lemur (pip), affecting versions < 1.9.0. It is fixed in 1.9.0.
CVE-2026-44305 has a CVSS score of 6.8 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
lemur (pip) versions < 1.9.0 is affected.
Yes. CVE-2026-44305 is fixed in 1.9.0. Upgrade to this version or later.
Whether CVE-2026-44305 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
Upgrade lemur to 1.9.0 or later.