CVE-2026-76238

stigmem versions before 0.9.0a12 contain a broken object level authorization vulnerability in the decay sweep endpoint that allows authenticated attackers with write credentials for one tenant to execute decay operations affecting all tenants. Attackers can submit POST requests to the decay sweep endpoint with ttl_seconds=0 to expire facts across all tenants, or use dry_run to obtain cross-tenant fact counts and existence information.

stigmem versions before 0.9.0a12 contain a broken object level authorization vulnerability in the decay sweep endpoint that allows authenticated attackers with write credentials for one tenant to execute decay operations affecting all tenants. Attackers can submit POST requests to the decay sweep endpoint with ttl_seconds=0 to expire facts across all tenants, or use dry_run to obtain cross-tenant fact counts and existence information.

Summary

On a multi-tenant stigmem node, a caller holding a write credential for one tenant can run a decay sweep that acts on every tenant's facts. The candidate-selection queries in lifecycle/decay.py (_select_ttl_candidates, _select_confidence_candidates) carried no tenant_id predicate, and the caller's tenant was not threaded into the sweep or its async worker (run_decay_sweep / _decay_job_worker), reached via POST /v1/decay/sweep.

Impact

A sweep with ttl_seconds=0 expires all tenants' facts — cross-tenant data destruction (integrity and availability). A dry_run sweep returns a global candidate count, acting as a cross-tenant existence/volume oracle (information disclosure).

Affected configurations

This is a cross-tenant break. It is exploitable only on deployments running the opt-in stigmem-plugin-multi-tenant (multiple tenants on one node). A default single-tenant node has only tenant="default" — there is no second tenant to cross — so it is not exploitable on default deployments. The rating is HIGH for the multi-tenant deployments the plugin exists to isolate.

Patches

Fixed in 0.9.0a12 (PR #728): identity.tenant_id is threaded into run_decay_sweep and _decay_job_worker, and AND tenant_id = ? was added to the candidate selectors and the graph-sync. A tenant-B sweep now leaves tenant-A facts untouched, and dry_run counts only the caller's tenant. The check_fact_query_tenant_scope.py CI guard was extended to scan lifecycle/ so this class cannot silently regress.

Workarounds

None other than upgrading to 0.9.0a12. Single-tenant deployments are unaffected.

stigmem versions before 0.9.0a12 contain a broken object level authorization vulnerability in the decay sweep endpoint that allows authenticated attackers with write credentials for one tenant to execute decay operations affecting all tenants. Attackers can submit POST requests to the decay sweep endpoint with ttl_seconds=0 to expire facts across all tenants, or use dry_run to obtain cross-tenant fact counts and existence information.

stigmem versions before 0.9.0a12 contain a broken object level authorization vulnerability in the decay sweep endpoint that allows authenticated attackers with write credentials for one tenant to execute decay operations affecting all tenants. Attackers can submit POST requests to the decay sweep endpoint with ttl_seconds=0 to expire facts across all tenants, or use dry_run to obtain cross-tenant fact counts and existence information.

stigmem versions before 0.9.0a12 contain a broken object level authorization vulnerability in the decay sweep endpoint that allows authenticated attackers with write credentials for one tenant to execute decay operations affecting all tenants. Attackers can submit POST requests to the decay sweep endpoint with ttl_seconds=0 to expire facts across all tenants, or use dry_run to obtain cross-tenant fact counts and existence information.

Summary

On a multi-tenant stigmem node, a caller holding a write credential for one tenant can run a decay sweep that acts on every tenant's facts. The candidate-selection queries in lifecycle/decay.py (_select_ttl_candidates, _select_confidence_candidates) carried no tenant_id predicate, and the caller's tenant was not threaded into the sweep or its async worker (run_decay_sweep / _decay_job_worker), reached via POST /v1/decay/sweep.

Impact

A sweep with ttl_seconds=0 expires all tenants' facts — cross-tenant data destruction (integrity and availability). A dry_run sweep returns a global candidate count, acting as a cross-tenant existence/volume oracle (information disclosure).

Affected configurations

This is a cross-tenant break. It is exploitable only on deployments running the opt-in stigmem-plugin-multi-tenant (multiple tenants on one node). A default single-tenant node has only tenant="default" — there is no second tenant to cross — so it is not exploitable on default deployments. The rating is HIGH for the multi-tenant deployments the plugin exists to isolate.

Patches

Fixed in 0.9.0a12 (PR #728): identity.tenant_id is threaded into run_decay_sweep and _decay_job_worker, and AND tenant_id = ? was added to the candidate selectors and the graph-sync. A tenant-B sweep now leaves tenant-A facts untouched, and dry_run counts only the caller's tenant. The check_fact_query_tenant_scope.py CI guard was extended to scan lifecycle/ so this class cannot silently regress.

Workarounds

None other than upgrading to 0.9.0a12. Single-tenant deployments are unaffected.