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Vulnerabilities

Vulnerability · CVE-2026-108434

Out-of-bounds read in Microsoft Office Word allows an unauthorized attacker to disclose information over a network.

Published Oct 15, 2026 · catalog updated Oct 16, 2026 · Microsoft Microsoft 365

Check if you run it

No confirmed exploitation is on record for CVE-2026-108434. EPSS is 0.51%. Act only if a listed version of Microsoft Microsoft 365 is installed.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.51%
Remediation
Advisory link
Affected products
microsoft Microsoft Office 365 for Mac · microsoft Microsoft Office LTSC 2021 for 32-bit editions · microsoft Microsoft Office LTSC 2021 for 64-bit editions · microsoft Microsoft Office LTSC 2024 for 32-bit editions · microsoft Microsoft Office LTSC 2024 for 64-bit editions · microsoft Microsoft Office LTSC for Mac 2021

Affected Microsoft products: Microsoft Office LTSC 2024 for 64-bit editions, Microsoft Office LTSC 2024 for 32-bit editions, Microsoft Office LTSC 2021 for 32-bit editions, Microsoft Office LTSC 2021 for 64-bit editions, Microsoft Office 365 for Mac, Microsoft Office LTSC for Mac 2024, Microsoft Office LTSC for Mac 2021.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • microsoft Microsoft Office 365 for Macversion unspecified
  • microsoft Microsoft Office LTSC 2021 for 32-bit editionsversion unspecified
  • microsoft Microsoft Office LTSC 2021 for 64-bit editionsversion unspecified
  • microsoft Microsoft Office LTSC 2024 for 32-bit editionsversion unspecified
  • microsoft Microsoft Office LTSC 2024 for 64-bit editionsversion unspecified
  • microsoft Microsoft Office LTSC for Mac 2021version unspecified
  • microsoft Microsoft Office LTSC for Mac 2024version unspecified

How to fix CVE-2026-108434

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-108434. EPSS is 0.51%. Act only if a listed version of Microsoft Microsoft 365 is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-125: Out-of-bounds Read. EPSS 0.51%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 15, 2026 · NIST NVD

    Detected

    Out-of-bounds read in Microsoft Office Word allows an unauthorized attacker to disclose information over a network.

  2. Oct 16, 2026 · NIST NVD

    Updated

    Out-of-bounds read in Microsoft Office Word allows an unauthorized attacker to disclose information over a network.

Sources

  • CVE.orgVulnerability recordCVE-2026-108434

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-108434

    30-day exploitation probability 0.5%

    first.org
  • Microsoft Security Update GuideVendor advisoryCVE-2026-108434

    Microsoft Office LTSC 2024 for 64-bit editions, Microsoft Office LTSC 2024 for 32-bit editions, Microsoft Office LTSC 2021 for 32-bit editions, Microsoft Office LTSC 2021 for 64-bit editions

    msrc.microsoft.com
  • NIST NVDVulnerability recordCVE-2026-108434

    Out-of-bounds read in Microsoft Office Word allows an unauthorized attacker to disclose information over a network.

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.