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PatchSiren cyber security CVE debrief

CVE-2026-39910 STACKIT CVE debrief

CVE-2026-39910 is a critical vulnerability in STACKIT IaaS API that allows authenticated, low-privileged attackers to escalate privileges to full organization compromise. The vulnerability is caused by a missing authorization check in the API, which allows attackers to attach arbitrary service accounts to virtual machines they control. This can be done by exploiting the unvalidated PUT servers service-accounts endpoint. Attackers can then query the Instance Metadata Service to retrieve OAuth2 tokens, bypassing tenant boundaries and gaining unauthorized control over the entire organization environment.

Vendor
STACKIT
Product
IaaS API
CVSS
HIGH 8.7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-08
Original CVE updated
2026-08-24
Advisory published
2026-06-08
Advisory updated
2026-08-24

Who should care

Administrators and users of STACKIT IaaS API should be aware of this vulnerability and take immediate action to patch their systems.

Technical summary

The vulnerability has a CVSS score of 9.3 and is classified as CRITICAL. The CVSS vector is CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X.

Defensive priority

high

Recommended defensive actions

  • Apply the patch as soon as possible to prevent exploitation.
  • Review and update access controls to ensure that only authorized users have access to the API.
  • Monitor the API for suspicious activity and implement additional security measures to detect and prevent attacks.

Evidence notes

The vulnerability was reported by [email protected] and is related to CWE-862.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-39910 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-39910

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-39910 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-39910

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.