AI analysis
OpenStack Octavia before 18.0.1 fails to validate the tls_ciphers field on listeners and pools when using the Amphora provider driver, allowing a newline and other control characters to be written verbatim into the HAProxy configuration generated inside the amphora VM. An authenticated project member who owns a TLS-enabled load balancer can exploit this to inject arbitrary HAProxy configuration directives. Because HAProxy terminates and routes tenant traffic, successful injection can let the attacker intercept, redirect, or tamper with load-balanced traffic and potentially pivot within the provider network, which is reflected in the critical CVSS 4.0 score of 9.4. Only deployments using the Amphora provider are affected, with the practical risk concentrated in multi-tenant clouds that expose load-balancer APIs to untrusted tenant accounts. No public proof of concept is known and the flaw is not on the CISA KEV list, so there is no indication of in-the-wild exploitation at this time.
What to do: Upgrade Octavia to 18.0.1 or later, and check your Linux distributor or vendor for backported fixes if you run a supported stable branch. Until patched, tighten Octavia RBAC/policy so only trusted roles can create or update listeners and pools, and audit existing tls_ciphers values plus the generated haproxy.cfg on amphorae for embedded newlines or unexpected directives. Review load-balancer audit logs for tenants setting odd cipher strings on TLS-enabled listeners or pools.
Affected
| OpenStack Octavia (Amphora provider driver) | before 18.0.1 |
Estimated exposure
moderate≈ thousands of OpenStack deployments (only Amphora-provider clouds), with tenant-user exposure potentially higher on multi-tenant public clouds — Octavia is the standard load-balancing service in modern OpenStack clouds, of which there are estimated to be in the low thousands in production (Open Infrastructure Foundation reporting puts OpenStack at tens of millions of cores), but…
Description
In OpenStack Octavia before 18.0.1, the Amphora provider driver did not validate the listener and pool tls_ciphers field for control characters. The value is written verbatim into the HAProxy configuration generated on the amphora, and thus an authenticated project member who owns a TLS-enabled load balancer can embed a newline and inject arbitrary HAProxy configuration directives. Only deployments using the Amphora provider are affected.