Security Digest · Vulnerability record
CVE-2023-44981: Authorization Bypass Through User-Controlled Key vulnerability in Apache ZooKeeper
Authorization Bypass Through User-Controlled Key vulnerability in Apache ZooKeeper.
CVSS 9.1 Critical EPSS 2.2% · p83
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 2.2%, percentile 83: FIRST’s model estimates a 2.2% chance of exploitation activity in the next 30 days, higher than 83% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
org.apache.zookeeper:zookeeper(Maven) < 3.7.2, fixed in 3.7.2;org.apache.zookeeper:zookeeper(Maven) >= 3.8.0, < 3.8.3, fixed in 3.8.3;org.apache.zookeeper:zookeeper(Maven) >= 3.9.0, < 3.9.1, fixed in 3.9.1. Check your lockfile, including transitive dependencies.
What it is
Authorization Bypass Through User-Controlled Key vulnerability in Apache ZooKeeper. If SASL Quorum Peer authentication is enabled in ZooKeeper (quorum.auth.enableSasl=true), the authorization is done by verifying that the instance part in SASL authentication ID is listed in zoo.cfg server list. The instance part in SASL auth ID is optional and if it's missing, like 'eve@EXAMPLE.COM', the authorization check will be skipped. As a result an arbitrary endpoint could join the cluster and begin propagating counterfeit changes to the leader, essentially giving it complete read-write access to the data tree. Quorum Peer authentication is not enabled by default. Users are recommended to upgrade to version 3.9.1, 3.8.3, 3.7.2, which fixes the issue. Alternately ensure the ensemble election/quorum communication is protected by a firewall as this will mitigate the issue. See the documentation for more details on correct cluster administration.
From the GitHub advisory
Authorization Bypass Through User-Controlled Key vulnerability in Apache ZooKeeper. If SASL Quorum Peer authentication is enabled in ZooKeeper (quorum.auth.enableSasl=true), the authorization is done by verifying that the instance part in SASL authentication ID is listed in zoo.cfg server list. The instance part in SASL auth ID is optional and if it's missing, like 'eve@EXAMPLE.COM', the authorization check will be skipped. As a result an arbitrary endpoint could join the cluster and begin propagating counterfeit changes to the leader, essentially giving it complete read-write access to the data tree. Quorum Peer authentication is not enabled by default.
Users are recommended to upgrade to version 3.9.1, 3.8.3, 3.7.2, which fixes the issue.
Alternately ensure the ensemble election/quorum communication is protected by a firewall as this will mitigate the issue.
See the documentation for more details on correct cluster administration.
Weakness type: CWE-639.
Product: org.apache.zookeeper:zookeeper (Maven) · Assigned by: apache · Published: 2023-10-11
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Maven | org.apache.zookeeper:zookeeper | < 3.7.2 | 3.7.2 |
| Maven | org.apache.zookeeper:zookeeper | >= 3.8.0, < 3.8.3 | 3.8.3 |
| Maven | org.apache.zookeeper:zookeeper | >= 3.9.0, < 3.9.1 | 3.9.1 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| Apache Software Foundation | Apache ZooKeeper | 3.9.0 < 3.9.1, 3.8.0 <= 3.8.2, 3.7.0 <= 3.7.1, < 3.7.0 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADP | 3.1 | 9.1 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| GitHub | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
- FIRST EPSS (model of 2026-10-21): 2.22% probability of exploitation activity in the next 30 days; percentile 83.
Timeline
- — CVE record published by apache
- — GitHub-reviewed advisory GHSA-7286-pgfv-vxvh published (critical)
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
- lists.apache.org lists.apache.org
Vulnerability records
- GitHub Advisory GHSA-7286-pgfv-vxvh github.com
- CVE.org record CVE-2023-44981 cve.org
- NVD entry CVE-2023-44981 nvd.nist.gov
Other references from the CVE record and advisory
- openwall.com openwall.com
- lists.debian.org lists.debian.org
- debian.org debian.org
- security.netapp.com security.netapp.com