CVE-2026-62764: Apache Accumulo Privilege Escalation Flaw

CVE-2026-62764 Overview

CVE-2026-62764 is an Improper Handling of Insufficient Privileges vulnerability [CWE-274] in Apache Accumulo. An authenticated user without system permissions can issue a remote command to gracefully shut down core system components. The affected components include compaction-coordinator, compactor, gc, manager, monitor, tserver, and sserver. Successful exploitation leads to a denial of service against the Accumulo cluster.

The issue affects Apache Accumulo 2.1.4 and 2.1.5. The Apache Accumulo project recommends upgrading to version 2.1.6, which fixes the issue.

Critical Impact
Any authenticated low-privileged user can trigger graceful shutdowns of core Accumulo services, causing cluster-wide denial of service without requiring administrative or system-level permissions.

Affected Products

Apache Accumulo 2.1.4
Apache Accumulo 2.1.5
Fixed in Apache Accumulo 2.1.6

Discovery Timeline

2026-07-17 - CVE-2026-62764 published to NVD
2026-07-17 - Apache Accumulo 2.1.6 released with the fix
2026-07-17 - Last updated in NVD database

Technical Details for CVE-2026-62764

Vulnerability Analysis

Apache Accumulo is a distributed key/value store built on Apache Hadoop, ZooKeeper, and Thrift. The platform exposes administrative RPC endpoints that manage the lifecycle of cluster components. These endpoints must enforce system-level authorization before executing privileged actions.

The vulnerability stems from missing authorization checks on the graceful shutdown command path. An authenticated user with only basic access, and without the required system permissions, can invoke the shutdown RPC against any core component. The server processes the command as if the caller were authorized.

The result is a denial of service. An attacker can iteratively shut down tserver, manager, gc, monitor, compactor, compaction-coordinator, and sserver processes, disabling read, write, and maintenance workloads across the cluster.

Root Cause

The root cause is Improper Handling of Insufficient Privileges [CWE-274]. The shutdown command handler does not verify that the caller holds the System.SYSTEM permission required to control cluster components. Authorization is required to authenticate, but not to execute the destructive action.

Attack Vector

The attack requires network access to the Accumulo services and valid credentials for any low-privileged account. The attacker sends a shutdown request to a targeted component through the standard Accumulo client interface. No user interaction is required beyond issuing the command, and no memory corruption or exploit primitive is needed.

No verified exploit code is available. See the GitHub Issue #6478 and the Apache Mailing List Thread for maintainer discussion of the fix.

Detection Methods for CVE-2026-62764

Indicators of Compromise

Unexpected graceful shutdown log entries in tserver, manager, gc, monitor, compactor, compaction-coordinator, or sserver process logs.
Shutdown RPC calls originating from user accounts that do not hold the System.SYSTEM permission.
Repeated component restarts or cluster availability drops that correlate with authenticated client sessions from non-administrative principals.

Detection Strategies

Audit Accumulo server logs for shutdown events and correlate the initiating principal against the roster of accounts granted system permissions.
Alert on any invocation of the shutdown RPC where the caller is not on an explicit administrator allowlist.
Baseline expected shutdown activity against maintenance windows and flag out-of-band shutdown commands.

Monitoring Recommendations

Forward Accumulo audit and process lifecycle logs to a centralized SIEM for retention and correlation.
Monitor cluster health metrics such as active tserver count and manager availability, and generate alerts on abrupt drops.
Track authentication events for low-privileged Accumulo users that immediately precede administrative RPC calls.

How to Mitigate CVE-2026-62764

Immediate Actions Required

Upgrade all Apache Accumulo installations running 2.1.4 or 2.1.5 to version 2.1.6.
Rotate credentials for Accumulo user accounts and audit which principals hold access to the cluster.
Restrict network reachability to Accumulo RPC ports so only trusted application hosts can connect.

Patch Information

Apache Accumulo 2.1.6 fixes the vulnerability by enforcing the required system permission on the shutdown command path. Download the release from Apache Accumulo Downloads and review the Apache Accumulo Release 2.1.6 notes. See the OpenWall OSS-Security Post for the public advisory.

Workarounds

Limit Accumulo account provisioning to trusted operators until the upgrade to 2.1.6 is complete.
Place Accumulo RPC endpoints behind network segmentation or firewall rules that restrict access to a small set of application servers.
Review and prune unused or shared low-privileged accounts that could be leveraged to issue shutdown commands.

bash

# Verify the running Accumulo version and upgrade to 2.1.6
accumulo version

# After upgrade, confirm all binaries report the fixed release
accumulo version | grep 2.1.6