Microsoft Partner Center: Externally Controlled Reference to a Resource in Another Sphere
CVE-2026-34327 is a high-severity externally controlled reference to a resource in another sphere vulnerability in Microsoft Partner Center from Microsoft, with a CVSS 3.1 base score of 8.2 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.64% chance of exploitation within 30 days, higher than 51% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Microsoft Partner Center you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on msrc.microsoft.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Microsoft | Microsoft Partner Center | Not specified in the record | Not stated |
| Microsoft | Partner Center | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N. Scored by CNA (microsoft.com).
Official description
Externally controlled reference to a resource in another sphere in Microsoft Partner Center allows an unauthorized attacker to perform spoofing over a network.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Externally Controlled Reference to a Resource in Another Sphere
The product uses an externally controlled name or reference that resolves to a resource that is outside of the intended control sphere.
More Externally Controlled Reference to a Resource in Another Sphere vulnerabilities (CWE-610)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in Microsoft Partner Center
- 9.8 Critical severity
Recent Externally Controlled Reference to a Resource in Another Sphere vulnerabilities
- 8.8 High severity
- 9.8 Critical severity
- 7.3 High severity
- 7.3 High severity
- 7.8 High severity
- 7.1 High severity
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