Microsoft Azure CycleCloud: OS command injection leads to local code execution
Summary
Azure CycleCloud, a cluster-management product for HPC and batch workloads on Azure, contains an OS command injection flaw (CWE-78). An attacker with local access to the CycleCloud host, a valid low-privilege account and a user interaction can execute code on the system. CycleCloud usually holds cloud credentials and can start compute resources, so a successful attack may have a significant impact on confidentiality, integrity and availability.
Affected
- Microsoft Azure CycleCloud 8.9.1 (CNA range: 1.0.0 to before 8.9.2)
- VulDB also lists 8.9.2; this conflicts with the CNA range and has not been verified
- Full affected range: to be confirmed in the Microsoft Security Update Guide
Fixed in
- Upgrade to Azure CycleCloud 8.9.2 or later (fix version not confirmed by the vendor advisory in the sources reviewed)
- Backports to earlier 8.x branches: Unknown.
Workaround
- Unknown. No vendor workaround found.
- Restrict the accounts that can log in to CycleCloud.
- Limit local shell access on the CycleCloud host.
Exploitation
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
- Rapid7: Exploitation Less Likely, not publicly disclosed.
- No public proof of concept or in-the-wild exploitation known.
- CISA KEV: not listed. EPSS about 0.004.
Our recommendation
- Check whether Azure CycleCloud is used in your environment.
- Update to 8.9.2 or later after confirming the fix in the Microsoft Security Update Guide.
- Review and reduce CycleCloud accounts and local access to the host.
- Monitor the host for unexpected command execution.
Information from Microsoft (Patch Tuesday October 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide msrc.microsoft.com
- VulDB vuldb.com
- Vulners NVD record vulners.com
- Vulners CVE list record vulners.com
- Rapid7 October 2026 Patch Tuesday www.rapid7.com
- Strix CVE record www.strix.ai
- CycleCloud 8.9.2 release notes github.com
- CycleCloud release notes learn.microsoft.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 3 Nov 2026, 02:12.
Original description (NVD)
Improper neutralization of special elements used in an os command ('os command injection') in Azure CycleCloud allows an authorized attacker to execute code locally.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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