CVE-2026-44304 is a high-severity security vulnerability in lemur (pip), affecting versions < 1.9.0. It is fixed in 1.9.0.
Description Overview Lemur's LDAP authentication module (lemur/auth/ldap.py) constructs LDAP search filters using unsanitized user input via Python string interpolation. An authenticated LDAP user can inject LDAP filter metacharacters through the username field to manipulate group membership queries and escalate their privileges to administrator. Vulnerable Code Location: lemur/auth/ldap.py, bind() method Filter 1, User lookup (line ~161): self.ldapprincipal is derived directly from args["username"] submitted at POST /auth/login with no sanitization. The ldap.filter.escapefilterchars() function is never called. Filter 2, Active Directory group lookup (line ~189): The userdn value is derived from the LDAP response to the first unsanitized query, making it potentially tainted as well. Impact An authenticated LDAP user can: Inject LDAP filter syntax into the username field during login Manipulate the group membership query to return arbitrary groups Be assigned the admin role or any other privileged role in Lemur Gain unauthorized access to all certificates, private keys (via /certificates/<id>/key), and CA configurations Issue certificates under any authority Exploitation Constraint The simplebinds() call must succeed before the injectable filter is reached, so the attacker requires valid LDAP credentials. This is a post-authentication privilege escalation. Steps to Reproduce Deploy Lemur with LDAP authentication enabled: python LDAPAUTH = True LDAPISACTIVEDIRECTORY = True LDAPBINDURI = "ldaps://dc.corp.example.com" LDAPBASEDN = "DC=corp,DC=example,DC=com" LDAPEMAILDOMAIN = "corp.example.com" Create a valid LDAP user account Send login request with crafted username containing LDAP metacharacters: POST /auth/login Content-Type: application/json { "username": "validuser)(memberOf=CN=LemurAdmins,DC=corp,DC=example,DC=com", "password": "validpassword" } The LDAP filter becomes: userPrincipalName=validuser)(memberOf=CN=LemurAdmins,DC=corp,DC=example,[email protected] Depending on the LDAP server's parsing, this can alter query semantics The user is assigned roles they should not have access to Remediation Apply ldap.filter.escapefilterchars() to all user-controlled values before interpolation: Resources CWE-90: https://cwe.mitre.org/data/definitions/90.html OWASP LDAP Injection: https://owasp.org/www-community/attacks/LDAPInjection Python ldap.filter.escapefilter_chars: https://www.python-ldap.org/en/python-ldap-3.4.0/reference/ldap-filter.html
CVE-2026-44304 has a CVSS score of 8.1 (High). The vector is network-reachable, low 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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CVE-2026-44304 is a high-severity security vulnerability in lemur (pip), affecting versions < 1.9.0. It is fixed in 1.9.0.
CVE-2026-44304 has a CVSS score of 8.1 (High). 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-2026-44304 is fixed in 1.9.0. Upgrade to this version or later.
Whether CVE-2026-44304 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.