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TI-2026-85016 Aliases CVE-2026-100235GHSA-f5cq-cgxv-j9m8

TOCTOU race in Apache ZooKeeper setACL bypasses ACL revocation

Priority LOW 27CWE-367Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
None · High · None
Fix status
Deferred Red Hat: fix deferred

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat.

Summary

Apache ZooKeeper from 3.8.0 through 3.8.7 and from 3.9.0 through 3.9.6 is affected. A time-of-check to time-of-use race condition (CWE-367) in setACL handling lets a request authorized under the old ACL commit after the ACL change takes effect. A client with low privileges can keep a revoked permission, including re-granting itself full permissions. In deployments moving from OPEN_ACL_UNSAFE to a restrictive ACL, an unauthenticated client can exploit this during the transition.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

Description from the CNA

Incorrect authorization due to a time-of-check to time-of-use (TOCTOU) race condition in the setACL request handling of Apache ZooKeeper. When a node's ACL is changed via setACL, the pending change is not published to the server's outstanding change record for that node. Any request that is prepared (and authorized) after the setACL is submitted but before it commits is therefore checked against the previous, pre-revocation ACL, yet is applied to the data tree after the ACL change has taken effect. A client that currently holds a permission can use this window to perform operations requiring that permission through and after its revocation — for example, committing writes or deletes after losing write access, or re-granting itself full permissions, which persistently defeats the revocation. In deployments transitioning from the default OPEN_ACL_UNSAFE ACL to a restrictive ACL, any unauthenticated client can exploit this during the transition. This issue affects Apache ZooKeeper up to and including 3.9.6. Users are recommended to upgrade to version 3.8.8 or 3.9.7, which fixes the issue.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00338 27th percentileScored 2026-11-07
Fix Deferred Red Hat: fix deferred

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
ApacheApache ZooKeeper3.9.0 – 3.9.6; 3.8.0 – 3.8.7—No fix listedCNA
  • Apache ZooKeeper VendorApache Affected 3.9.0 – 3.9.6; 3.8.0 – 3.8.7 Fixed in — No fix listed CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:apache:zookeeper:*:*:*:*:*:*:*:*——Apache
  • cpe:2.3:a:apache:zookeeper:*:*:*:*:*:*:*:* Versions — — ·Apache

Remediation

Upgrade Apache ZooKeeper to 3.8.8 or 3.9.7, which fix the issue. Red Hat Fuse 7 has no fix planned, and Red Hat AMQ Broker 7, Red Hat Offline Knowledge Portal and Red Hat OpenShift AI have no fix available.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat AMQ Broker 7AffectedNo fix yet: Fix deferred
Red Hat Fuse 7AffectedNo fix planned: Out of support scope
Red Hat Offline Knowledge PortalAffectedNo fix yet: Fix deferred
Red Hat OpenShift AI (RHOAI)AffectedNo fix yet: Fix deferred

Timeline

  1. 2026-11-04 Threatist record created from CVE-2026-100235
  2. 2026-11-04 Alias added: GHSA-f5cq-cgxv-j9m8
  3. 2026-11-04 Affected versions changed · Red Hat
  4. 2026-11-04 CVSS score added · Red Hat
  5. 2026-11-05 CISA SSVC decision points changed
  6. 2026-11-05 Priority changed: MEDIUM → LOW

References

Advisory 1

  • TI-2025-18529 Apache Tomcat: Potential RCE and/or information disclosure and/or information corruption with partial PUT KEVCVSS 3.1CRITICAL 10.0
  • TI-2024-30292 Apache OFBiz: Confused controller-view authorization logic (forced browsing) KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-26062 Apache OFBiz: Unauthenticated endpoint could allow execution of screen rendering code KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-21190 Apache OFBiz: Path traversal leading to RCE KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-18186 Apache HugeGraph-Server: Command execution in gremlin KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-25106 Deserialization of untrusted data in Apache ActiveMQ KEVCVSS 3.1CRITICAL 10.0
See all 4053 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences