CVE-2026-39910

STACKIT IaaS API Privilege Escalation via Service Account Attachment

Published Jun 8, 2026 CVSS 4.0 · 7.7 High EPSS < 1% KEV · Not listed
Description
STACKIT IaaS API contains a missing authorization check in the PUT servers service-accounts endpoint. An authenticated, low-privileged attacker can attach an arbitrary service account to a virtual machine they control without validation of their permission to use it, then query the Instance Metadata Service (IMDS) to retrieve an OAuth2 token for that service account and act with its privileges. The impact is confined to the attacker’s own project. The STACKIT Identity Provider enforces strict project matching between the target VM and the requested service account during token impersonation, so cross-project and cross-organization exploitation is not possible. Any further access is bounded by the IAM roles already assigned to the targeted service account.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Description STACKIT IaaS API contains a missing authorization check vulnerability that allows authenticated, low-privileged attackers to escalate privileges to full organization compromise by attaching arbitrary service accounts to virtual machines they control. Attackers can exploit the unvalidated PUT servers service-accounts endpoint to attach high-privileged service accounts and query the Instance Metadata Service to retrieve OAuth2 tokens, bypassing tenant boundaries and gaining unauthorized control over the entire organization environment. STACKIT IaaS API contains a missing authorization check in the PUT servers service-accounts endpoint. An authenticated, low-privileged attacker can attach an arbitrary service account to a virtual machine they control without validation of their permission to use it, then query the Instance Metadata Service (IMDS) to retrieve an OAuth2 token for that service account and act with its privileges. The impact is confined to the attacker’s own project. The STACKIT Identity Provider enforces strict project matching between the target VM and the requested service account during token impersonation, so cross-project and cross-organization exploitation is not possible. Any further access is bounded by the IAM roles already assigned to the targeted service account.
Metrics cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

cvssV4_0

{'score': 7.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 9.3, 'vector': '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'}

cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Stackit
Stackit iaas Api
Vendors & Products Stackit
Stackit iaas Api
Type Values Removed Values Added
Description STACKIT IaaS API contains a missing authorization check vulnerability that allows authenticated, low-privileged attackers to escalate privileges to full organization compromise by attaching arbitrary service accounts to virtual machines they control. Attackers can exploit the unvalidated PUT servers service-accounts endpoint to attach high-privileged service accounts and query the Instance Metadata Service to retrieve OAuth2 tokens, bypassing tenant boundaries and gaining unauthorized control over the entire organization environment.
Title STACKIT IaaS API Privilege Escalation via Service Account Attachment
Weaknesses CWE-862
References
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 9.3, 'vector': '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Oct 30, 2026, 5:12 PM
Reserved
Apr 7, 2026, 8:57 PM
Status
Deferred
Published
Jun 8, 2026, 5:16 PM
Modified
Oct 30, 2026, 5:17 PM