CVE-2025-53739: Microsoft 365 Apps for Enterprise · Type Confusion
Affects Microsoft 365 Apps for EnterpriseSource CVE Database V5
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 46% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:CExploitation evidence
Disclosed: evidence found.
CVE published 12 Aug 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Microsoft Microsoft 365 Apps for Enterprise | Affected
| Fixed in– |
AI-suggested
To mitigate CVE-2025-53739 effectively, organizations should implement a multi-layered approach beyond generic patching advice. First, restrict local access to systems running Microsoft 365 Apps for Enterprise to trusted users only, minimizing exposure. Employ application whitelisting and endpoint protection solutions that can detect and block execution of suspicious code spawned by Excel processes. Enforce strict macro and ActiveX control policies within Excel to prevent automatic execution of potentially malicious content. Educate users to recognize and avoid opening unexpected or suspicious Excel files, especially from untrusted sources, to reduce the risk of social engineering. Monitor endpoint and network logs for unusual Excel activity or process spawning indicative of exploitation attempts. Use sandboxing or virtualization for opening untrusted Excel files to contain potential attacks. Maintain up-to-date backups and incident response plans to recover quickly if exploitation occurs. Finally, stay alert for official patches or advisories from Microsoft and apply them promptly once available, as no patches are currently released.
Description
Access of resource using incompatible type ('type confusion') in Microsoft Office Excel allows an unauthorized attacker to execute code locally.