Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Lemur versions before 1.9.3 are affected. An authenticated user who has been granted membership in an ACME authority's role can change that authority's acme_url through the update endpoint, which skips the host allowlist check applied at creation. When certificates are later issued through that authority, Lemur's backend requests the attacker-chosen URL, which enables server-side request forgery against internal services and cloud metadata endpoints. Upgrade to Lemur 1.9.3.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 7.7 | High | 3.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0028, the 20th percentile, on 11 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:39 UTC First seen by agentprime
- 31 Oct 2026, 14:39 UTC Confirmed by OSV