CVE-2026-76827: Search-indexer: search-indexer: update/delete operations not scoped to caller's cluster (cross-tenant data tampering)

Severity: medium (CVSS 6.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-19 · updated 2026-10-26
Weakness: CWE-693

Description

A flaw was found in search-indexer. This vulnerability allows a registered and authenticated managed cluster to tamper with or delete another cluster's indexed search data. This is possible because the delta-sync write paths in search-indexer do not properly restrict UPDATE/DELETE operations to data owned by the calling cluster. An attacker could exploit this by crafting specific user identifiers (UIDs) with a different cluster's prefix.

Affected products

Red Hat Advanced Cluster Management for Kubernetes 2.11: all versions — fixed in 1787688957
Red Hat Advanced Cluster Management for Kubernetes 2.13: all versions — fixed in 1787262474
Red Hat Advanced Cluster Management for Kubernetes 2.14: all versions — fixed in 1787250074
Red Hat Advanced Cluster Management for Kubernetes 2.15: all versions — fixed in 1787249293
Red Hat Advanced Cluster Management for Kubernetes 2.16: all versions — fixed in 1787248491
Red Hat Advanced Cluster Management for Kubernetes 2.17: all versions — fixed in 1787247085

How to fix

Upgrade to a fixed version: Red Hat Advanced Cluster Management for Kubernetes 2.11 1787688957; Red Hat Advanced Cluster Management for Kubernetes 2.13 1787262474; Red Hat Advanced Cluster Management for Kubernetes 2.14 1787250074; Red Hat Advanced Cluster Management for Kubernetes 2.15 1787249293; Red Hat Advanced Cluster Management for Kubernetes 2.16 1787248491; Red Hat Advanced Cluster Management for Kubernetes 2.17 1787247085. Check the vendor advisory for mitigations.

References

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