CVE-2026-100300: Apache ZooKeeper: Unauthenticated persistent denial of service via unvalidated quota-node data and paths crashing the transaction-apply thread
CVE-2026-100300 key facts
- CISA KEV
- Not listed (catalogue checked )
- Highest advisory rating
- High
- CVSS base score
- 8.7 (Apache), 7.5 (Red Hat)
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N· base score 8.7, scored by apacheAttack vector: network. Attack complexity: low. Attack requirements: none. Privileges required: none. User interaction: none. Confidentiality impact on the vulnerable system: none. Integrity impact on the vulnerable system: none. Availability impact on the vulnerable system: high. Confidentiality impact on subsequent systems: none. Integrity impact on subsequent systems: none. Availability impact on subsequent systems: none.- Weakness
- CWE-755 — Improper Handling of Exceptional Conditions
- CISA SSVC
- Exploitation: none observed. Automatable: yes. Technical impact: partial. CISA, .
- Fixed releases
- Apache: 3.8.8, 3.9.7
- Red Hat: 3.8.8, 3.9.7
- Assigned by
- apache (CNA)
- CVE record published
- Listed by VulniPulse
- Record changed
Ratings, versions and fixes are quoted from the vendor advisories that cover only CVE-2026-100300; each belongs to its advisory, not to every product listed. How records are collected and checked.
Description
Improper handling of exceptional conditions in the quota subsystem of Apache ZooKeeper allows an attacker able to write under the /zookeeper/quota subtree — unauthenticated on default deployments, where that subtree is world-writable — to crash the server's critical request-processing thread and render the on-disk data directory permanently unbootable. 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.
Text from the CVE.org record (apache).
How do I fix CVE-2026-100300?
Upgrade to a fixed release named by the vendor:
- Apache: 3.8.8, 3.9.7
- Red Hat: 3.8.8, 3.9.7
- Users are recommended to upgrade to version 3.8.8 or 3.9.7, which fixes the issue. (Apache)
Vendor advisories for CVE-2026-100300
Apache
1 advisory- Advisory severityHigh8.7
High [CVE-2026-100300] Improper handling of exceptional conditions in the quota subsystem of Apache ZooKeeper allows an attacker able to write under the /zookeeper/quota subtree — unauthenticated on default deployments, where that subtree is world-writable — to crash the server's critical request-processing thread and render the on-disk data directory permanently unbootable
CVE-2026-100300Source published Source updated
Improper handling of exceptional conditions in the quota subsystem of Apache ZooKeeper allows an attacker able to write under the /zookeeper/quota subtree — unauthenticated on default deployments, where that subtree is world-writable — to crash the server's critical request-processing thread and render the on-disk data directory permanently unbootable. 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.
- Affected products in this advisory
- Apache ZooKeeper
- Source-reported affected versions
- 3.9.6
- Source-reported fixed versions
- 3.8.8
- 3.9.7
- Mitigation guidance
- Users are recommended to upgrade to version 3.8.8 or 3.9.7, which fixes the issue.
Red Hat
1 advisory- Advisory severityHigh7.5
High [CVE-2026-100300] Denial of Service via improper exception handling in quota subsystem
CVE-2026-100300Source published Source updated
Denial of Service via improper exception handling in quota subsystem. Red Hat rates this important (CVSS 7.5). Weakness: CWE-248.
- Related products — impact not confirmed
- No product details extracted. Check the source bulletin.
- Source-reported affected versions
- 3.9.6
- Source-reported fixed versions
- 3.8.8
- 3.9.7
- Mitigation guidance
- No mitigation guidance extracted; consult the source.
References
Timeline
- CVE record published
- First vendor advisory listed by VulniPulse
- CVE record last updated
More Apache advisories
CVE-2026-100302Nov 4, 2026Apache ZooKeeper denial of serviceCVE-2026-115448Nov 4, 2026Apache ZooKeeper: Unbounded recursion in snapshot serializationCVE-2026-100252Nov 4, 2026Improper Authorization vulnerability in Apache ZooKeeperCVE-2026-100235Nov 4, 2026Apache ZooKeeper: ACL enforcement bypassCVE-2026-79993Sep 16, 2026Apache ZooKeeper: The `deleteContainer` opcode (0x14/20) is processed without verifyingCVE-2026-59969Sep 16, 2026Apache ZooKeeper quorum TLS fails to enforce peer hostname verification in FIPS-mode
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