CVE-2026-55163 Lemur: Privilege escalation via PUT /api/1/roles/<id> — non-admin role members can rewrite role membership
Non-admin role members can modify role membership and names, enabling lateral privilege escalation and access denial in Lemur certificate management.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-55163?
CVE-2026-55163 is a medium-severity missing authorization vulnerability in Netflix lemur, published on 18 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Lemur manages TLS certificate creation. Prior to 1.9.2, PUT /api/1/roles/ in lemur/roles/views.py:298 authorized updates with RoleMemberPermission(role_id), which allowed either an administrator or any existing member of the target role. The handler passed data["users"] and data["name"] to service.update, allowing a non-admin member to add or remove other users and rename the role. This enabled lateral privilege grants within roles that control certificate and authority access and could deny access by removing legitimate members. The DELETE handler already required admin_permission, confirming that the weaker PUT authorization was inconsistent. The fix applies the same administrator-only requirement to the PUT handler. This issue is fixed in version 1.9.2.
Weakness: CWE-863
Which versions are affected by CVE-2026-55163?
3 open source packages ship an affected version, including lemur.
| Package | Affected | Fixed in |
|---|---|---|
lemur PyPI | All versions | 1.9.2 |
lemur PyPI | All versions | 1.9.2 |
lemur PyPI | All versions | 1.9.2 |
How do I fix CVE-2026-55163?
Upgrade lemur to 1.9.2 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-55163 being exploited?
There is no known exploitation of CVE-2026-55163 in the wild and no public exploit code.
Sources
Also known as GHSA-x3vf-mgxj-7785, PYSEC-2026-2591.