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CVE-2026-55057 Microsoft CVE debrief

CVE-2026-55057 is an integer overflow or wraparound vulnerability in Microsoft Office. The vulnerability allows an unauthorized attacker to disclose information locally. Microsoft has released a patch for this vulnerability. The vulnerability has a CVSS score of 5.5 and a severity of MEDIUM. System administrators and users of Microsoft Office should be aware of this vulnerability and take steps to mitigate it.

Vendor
Microsoft
Product
Microsoft 365 Apps for Enterprise
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-14
Original CVE updated
2026-07-16
Advisory published
2026-07-14
Advisory updated
2026-07-16

Who should care

System administrators and users of Microsoft Office should be aware of this vulnerability and take steps to mitigate it. The vulnerability can be mitigated by applying the patch released by Microsoft, ensuring that Microsoft Office is up to date, and monitoring for suspicious activity.

Technical summary

The vulnerability is caused by an integer overflow or wraparound in Microsoft Office. This can allow an attacker to disclose information locally. The vulnerability has a CVSS score of 5.5 and a severity of MEDIUM. The affected product is Microsoft Office, and the vulnerability can be mitigated by applying the patch released by Microsoft.

Defensive priority

Medium priority

Recommended defensive actions

  • Apply the patch released by Microsoft
  • Ensure that Microsoft Office is up to date
  • Monitor for suspicious activity
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record for CVE-2026-55057 was published on 2026-07-14T18:18:17.953Z and was last modified on 2026-07-16T14:40:40.007Z. The NVD entry is currently Analyzed. The vulnerability is an integer overflow or wraparound in Microsoft Office, which allows an unauthorized attacker to disclose information locally. The source details are limited, and defenders should verify the affected scope and vendor guidance.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-55057 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-55057

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-55057 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-55057

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.