Security Digest · Vulnerability record
CVE-2026-112816: Improper certificate validation in the HTTPS listener in LXD
Improper certificate validation in the HTTPS listener in Canonical LXD 4.0.14, 5.0.10, 5.21.8, 6.9 before 4.0.15, 5.0.11, 5.21.9, 6.10.1 allows an unauthenticated attacker to authenticate as any trusted client and gain full access to the cluster and managed virtual machines via a crafted certificate chain.
CVSS 10.0 Critical EPSS 0.3% · p23 Check exposure
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.3%, percentile 23: FIRST’s model estimates a 0.3% chance of exploitation activity in the next 30 days, higher than 23% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Check exposure. LXD and MicroCloud mTLS Auth Bypass CVE-2026-112816 — Only LXD hosts with the HTTPS API enabled, which includes every cluster and MicroCloud, are at risk, but there the bug is a full authentication bypass to root, so refresh the snap this week.
What it is
Improper certificate validation in the HTTPS listener in Canonical LXD 4.0.14, 5.0.10, 5.21.8, 6.9 before 4.0.15, 5.0.11, 5.21.9, 6.10.1 allows an unauthenticated attacker to authenticate as any trusted client and gain full access to the cluster and managed virtual machines via a crafted certificate chain.
Weakness type: CWE-295.
Product: Canonical LXD · Assigned by: canonical · Published: 2026-10-30
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| Canonical | LXD | 4.0.14 < 4.0.15, 5.0.10 < 5.0.11, 5.21.8 < 5.21.9, 6.9.0 < 6.10.1 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| canonical | 4.0 | 10 Critical | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Attack requirements: none
- Privileges required: none (no login)
- User interaction: none
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
- FIRST EPSS (model of 2026-11-04): 0.30% probability of exploitation activity in the next 30 days; percentile 23.
Timeline
- — erroneo.us brief: LXD and MicroCloud mTLS Auth Bypass CVE-2026-112816
- — CVE record published by canonical
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
- github.com github.com
- discourse.ubuntu.com discourse.ubuntu.com
- discourse.ubuntu.com discourse.ubuntu.com
- discourse.ubuntu.com discourse.ubuntu.com
- discourse.ubuntu.com discourse.ubuntu.com
- discourse.ubuntu.com discourse.ubuntu.com
Vulnerability records
- CVE.org record CVE-2026-112816 cve.org
- NVD entry CVE-2026-112816 nvd.nist.gov