Security readout for executives and security teams
Plain-English summary
This issue affects Apache Hadoop YARN when the CapacityScheduler uses the optional ZKConfigurationStore. If an attacker can access ZooKeeper, malicious stored data can be deserialized and lead to arbitrary commands running as the YARN user.
Executive priority
Treat as high priority for Hadoop clusters using this optional configuration, because successful exploitation can execute commands under the YARN service account. Clusters not using ZKConfigurationStore appear less exposed based on the provided sources.
Technical view
CVE-2021-25642 is a CWE-502 unsafe deserialization flaw in Apache Hadoop YARN ZKConfigurationStore. Affected Hadoop ranges include 2.9.0-2.10.1, 3.0.0-alpha1-3.1.4, 3.2.0-3.2.3, and 3.3.0-3.3.3. Fixed versions include 2.10.2, 3.2.4, 3.3.4, or later with YARN-11126.
Likely exposure
Exposure is likely limited to Hadoop YARN deployments using CapacityScheduler with ZKConfigurationStore enabled. Risk rises materially where untrusted users, compromised services, or broad internal networks can reach ZooKeeper.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. Exploitation requires access to ZooKeeper and targets serialized configuration data consumed by YARN, with resulting command execution as the YARN user.
Researcher notes
The sources provide clear affected version ranges and fixed versions, but no CVSS score, proof of exploitation, or KEV status. Validation should focus on scheduler configuration, ZooKeeper trust boundaries, and confirming patched Hadoop builds.
Mitigation direction
- Upgrade Hadoop to 2.10.2, 3.2.4, 3.3.4, or later.
- Confirm deployed versions include the YARN-11126 fix.
- Restrict ZooKeeper access to trusted Hadoop components only.
- Review Apache and downstream vendor guidance for environment-specific instructions.
- Prioritize clusters using CapacityScheduler with ZKConfigurationStore.
Validation and detection
- Inventory Hadoop versions across all YARN clusters.
- Check whether CapacityScheduler uses ZKConfigurationStore.
- Verify ZooKeeper is not reachable by untrusted users or systems.
- Confirm the installed build contains YARN-11126.
- Review vendor advisories for downstream product exposure.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-502: Code execution behavior lookup
Code execution and unsafe deserialization weaknesses often justify reviewing execution behavior and process telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-25642 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://lists.apache.org/thread/g6vf2h4wdgzzdgk91mqozhs58wotq150CVE reference
- https://security.netapp.com/advisory/ntap-20221201-0003/CVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Deserialization of Untrusted Data
Deserialization of Untrusted Data represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.