CVE-2026-44304: Lemur: LDAP Filter Injection enables post-authentication privilege escalation

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-12 · updated 2026-10-26
Weakness: CWE-90

Description

Lemur manages TLS certificate creation. Prior to 1.9.0, 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. This vulnerability is fixed in 1.9.0.

Affected products

Netflix lemur: before 1.9.0

References

https://github.com/Netflix/lemur/security/advisories/GHSA-3r34-vq8m-39gh
https://github.com/Netflix/lemur/security/advisories/GHSA-3r34-vq8m-39gh

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