GHSA-v2wp-frmc-5q3v: lemur (CVE-2026-55166)

Package	Ecosystem	Affected	Fixed in
lemur	PyPI	<1.9.2	1.9.2

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Lemur versions before 1.9.2 are affected. An attacker with any valid SSO login, which Lemur auto-provisions as an active user, can point an ACME authority at a server-side URL such as the cloud instance metadata service to obtain the Lemur worker's cloud role credentials. The same flaw lets the original creator of a certificate keep fetching its private key after ownership is transferred. Upgrade to Lemur 1.9.2. The source gives few details on other workarounds, and no workaround is listed.

Written 10 Nov 2026.

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
9.9	Critical	3.1	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0029, the 21st percentile, on 13 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

This record came from the full history of the GitHub Advisory Database, published 29 Jun 2026. New records show when each source confirmed them.

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.