CVE-2025-55243
Published: 09 September 2025
Summary
CVE-2025-55243 is a high-severity Exposure of Sensitive Information to an Unauthorized Actor (CWE-200) vulnerability in Microsoft Officeplus. Its CVSS base score is 7.5 (High).
Operationally, ranked in the top 18.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
Deeper analysis
CVE-2025-55243 is an exposure of sensitive information vulnerability, tracked as CWE-200, that affects Microsoft Office Plus. It received a CVSS 3.1 base score of 7.5 reflecting a network attack vector, low attack complexity, no required privileges or user interaction, and high impact on confidentiality with no integrity or availability consequences.
An unauthenticated attacker can exploit the flaw remotely over a network to conduct spoofing attacks that result in unauthorized disclosure of sensitive information.
Microsoft has published an advisory for the issue at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-55243. The associated EPSS score remains flat at 0.0155 with no material increase observed after disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-27337
Vulnerability details
Exposure of sensitive information to an unauthorized actor in Microsoft Office Plus allows an unauthorized attacker to perform spoofing over a network.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Automated marking applies security attributes to system outputs, making it harder for attackers to exploit unmarked sensitive information leading to unauthorized exposure.
Proper attribute retention and permitted-value enforcement limits unauthorized actors from accessing sensitive information lacking correct labels.
Prevents unauthorized exposure of sensitive information by prohibiting untrusted external systems from processing or storing it.
By enforcing authorization matching prior to sharing, the control reduces the risk of exposing sensitive information to unauthorized actors.
Review and removal of nonpublic information from publicly accessible systems directly prevents exposure of sensitive data to unauthorized actors.
Data mining protection mechanisms detect and block unauthorized bulk extraction of sensitive data, directly mitigating exposure to unauthorized actors.
Literacy training teaches users to recognize and avoid actions that result in unauthorized exposure of sensitive information.
Retaining and monitoring training records confirms personnel have completed privacy and security awareness training on handling sensitive data, reducing the chance of unauthorized exposure due to lack of knowledge.