CVE-2021-42306
An information disclosure vulnerability manifests when a user or an application uploads unprotected private key data as part of an authentication certificate keyCredential on an Azure AD Application or Service Principal (which is not recommended).
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (3.27%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
An information disclosure vulnerability manifests when a user or an application uploads unprotected private key data as part of an authentication certificate keyCredential on an Azure AD Application or Service Principal (which is not recommended). This vulnerability allows a user or service in the tenant with application read access to read the private key data that was added to the application. Azure AD addressed this vulnerability by preventing disclosure of any private key values added to the application. Microsoft has identified services that could manifest this vulnerability, and steps that customers should take to be protected. Refer to the FAQ section for more information. For more details on this issue, please refer to the MSRC Blog Entry.
- CVSS 3.1
- 8.1 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 3.27% probability · 88th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-522
- Affected
- microsoft/azure active directory · microsoft/azure active site recovery · microsoft/azure automation · microsoft/azure migrate
- Source
- secure@microsoft.com
EPSS 3.3% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.