Lemur: LDAP Filter Injection enables post-authentication privilege escalation

published 2026-05-06 6 mo ago modified 2026-10-26 14 d ago also EUVD-2026-29864 , GHSA-3r34-vq8m-39gh , PYSEC-2026-2585

cvss: 8.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 12%
public exploits: 0; none known

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.

Patch / fix

fixed in 2 links 1

pypi lemur 1.9.0
netflix lemur 1.9.0

github.com/Netflix/lemur/releases/tag/v1.9.0 release

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 5 mo ago (2026-05-14)

Exploit prediction

0.22% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/Netflix/lemur/security/advisories/GHSA-3r34-vq8m-39gh referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.1	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
GitHub	3.1	8.1	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
OSV	3.1	8.1	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem	package	affected	fixed in
pypi	lemur	<1.9.0	1.9.0

Affected products

Netflix lemur

Classification

Weakness

CWE-90 Improper Neutralization of Special Elements used in an LDAP Query

References

github.com /Netflix/lemur/security/advisories/GHSA-3r34-vq8m-39gh
exploit, web
nvd.nist.gov /vuln/detail/CVE-2026-44304
advisory
github.com /Netflix/lemur
package
github.com /Netflix/lemur/releases/tag/v1.9.0
web
pypi.org /project/lemur
package
github.com /advisories/GHSA-3r34-vq8m-39gh
advisory

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary