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CVE Record

CVE-2021-32829: Post-authentication Remote Code Execution (RCE) in ZStack REST API

ZStack is open source IaaS(infrastructure as a service) software aiming to automate datacenters, managing resources of compute, storage, and networking all by APIs. Affected versions of ZStack REST API are vulnerable to post-authentication Remote Code Execution (RCE) via bypass of the Groovy shell sandbox. The REST API exposes the GET zstack/v1/batch-queries?script endpoint which is backed up by the BatchQueryAction class. Messages are represented by the APIBatchQueryMsg, dispatched to the QueryFacadeImpl facade and handled by the BatchQuery class. The HTTP request parameter script is mapped to the APIBatchQueryMsg.script property and evaluated as a Groovy script in BatchQuery.query the evaluation of the user-controlled Groovy script is sandboxed by SandboxTransformer which will apply the restrictions defined in the registered (sandbox.register()) GroovyInterceptor. Even though the sandbox heavily restricts the receiver types to a small set of allowed types, the sandbox is non effective at controlling any code placed in Java annotations and therefore vulnerable to meta-programming escapes. This issue leads to post-authenticated remote code execution. For more details see the referenced GHSL-2021-065. This issue is patched in versions 3.8.21, 3.10.8, and 4.1.0.

CriticalCVSS 9.6Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

CVE-2021-32829 lets an authenticated user execute code through the ZStack REST API by escaping a Groovy script sandbox. The risk is highest where ZStack management APIs are reachable by administrators, automation, or exposed management networks. Patched versions are named in the advisories.

Executive priority

Prioritize this for any production ZStack environment. It affects infrastructure management software, requires only authenticated access, and can allow code execution. Confirm exposure and upgrade before routine maintenance windows if the REST API is reachable by broad user groups or automation credentials.

Technical view

The vulnerable batch query endpoint maps a user-controlled script parameter into APIBatchQueryMsg.script and evaluates it as Groovy. The SandboxTransformer restrictions are bypassable through annotation/meta-programming behavior, causing post-authentication remote code execution. Affected ZStack ranges are below 3.8.21, 3.10.0 through before 3.10.8, and 4.0.0 through before 4.1.0.

Likely exposure

Exposure is limited to organizations running affected ZStack versions with REST API access available to authenticated users or automation. The source bundle lists no CPEs, so asset owners should validate installed ZStack versions directly rather than relying only on scanner product matching.

Exploitation context

The provided sources support post-authentication RCE and a CVSS 9.6 rating. They do not show CISA KEV listing or confirmed active exploitation for this CVE. Treat the issue as serious because low-privilege authenticated access can become code execution in the ZStack control plane.

Researcher notes

The key trust boundary is Groovy evaluation behind the REST API batch query path. The vulnerability is a sandbox escape rather than an unauthenticated endpoint flaw. Evidence in the bundle supports affected versions and fixed releases, but not active exploitation or alternate vendor mitigations.

Mitigation direction

  • Upgrade ZStack to 3.8.21, 3.10.8, 4.1.0, or later supported releases.
  • Restrict ZStack REST API access to trusted management networks and necessary administrators.
  • Review the GitHub advisory for branch-specific remediation guidance.
  • Monitor authenticated REST API activity until patch status is confirmed.
  • Rotate ZStack API credentials if suspicious authenticated activity is found.

Validation and detection

  • Inventory all ZStack deployments and record exact installed versions.
  • Compare versions with the affected ranges in the CVE and GitHub advisory.
  • Confirm whether the REST API is reachable outside trusted management paths.
  • Review logs for unexpected authenticated batch-query or script-related API use.
  • Verify upgraded systems report a patched ZStack release.
Prepared
Confidence
high
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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 · medium confidence lookup

CWE-94: 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.

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description · low confidence lookup

Execution 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.

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cve · low confidence lookup

CVE-2021-32829 mapping review

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Vulnerability profileCVE Program record
Severity
Critical
CVSS
9.6 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

Official CVE source material

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.

1CVSS vectors
0Timeline events
0ADP providers
4Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
9.6CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N3.15.8Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

9.6Critical
CVSS 3.1 vector shape for CVE-2021-32829Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
zstackiozstack< 3.8.21, >=3.10.0, < 3.10.8, >=4.0.0, < 4.1.0Listed
Weakness

CWE details

CWE-94

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.