CVE-2026-55166
Authenticated SSRF + auth flaw in Lemur exposes cloud credentials and private keys.
Is CVE-2026-55166 being exploited?
Not confirmed. CVE-2026-55166 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.28% probability of exploitation in the next 30 days.
How severe is CVE-2026-55166?
CVE-2026-55166 is rated Critical. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-55166?
Yes. A fix has been recorded for CVE-2026-55166. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-55166 affect?
CVE-2026-55166 affects Lemur < 1.9.2, Lemur ACME integrations, Instances hosting Lemur. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-55166?
Upgrade to Lemur 1.9.2, rotate affected keys/creds, audit key exports, restrict network egress.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated attacker can trigger SSRF to cloud metadata/internal services to steal cloud credentials and retain/export long-lived PKI private keys.
Immediate action required
- affected< 1.9.2
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.