CVE-2026-34179: Update of type field in restricted TLS certificate allows privilege escalation to cluster admin

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-04-09 · updated 2026-10-26
Weakness: CWE-915

Description

In Canonical LXD versions 4.12 through 6.7, the doCertificateUpdate function in lxd/certificates.go does not validate the Type field when handling PUT/PATCH requests to /1.0/certificates/{fingerprint} for restricted TLS certificate users, allowing a remote authenticated attacker to escalate privileges to cluster admin.

Affected products

Canonical LXD: from 4.12 through 5.0.6; from 5.21.0 through 5.21.4; from 6.0 through 6.7

References

https://github.com/canonical/lxd/pull/17936
https://github.com/canonical/lxd/security/advisories/GHSA-c3h3-89qf-jqm5
https://github.com/canonical/lxd/security/advisories/GHSA-c3h3-89qf-jqm5

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