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VulnerabilityPublished Updated

CVE-2025-53739: Microsoft 365 Apps for Enterprise · Type Confusion

Affects Microsoft 365 Apps for EnterpriseSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
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:C

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 12 Aug 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
Microsoft Microsoft 365 Apps for EnterpriseAffected
  • =16.0.1
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.

References

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