Out-of-bounds read in Microsoft Office for macOS and Microsoft Word - CVE-2026-63531

Vulnerability details

The vulnerability allows a remote attacker to disclose sensitive information.

The vulnerability exists due to out-of-bounds read in Microsoft Office Word when parsing a crafted Office file. A remote attacker can trick the victim into opening a crafted file to disclose sensitive information.

The disclosed data may include portions of process memory. The Preview Pane is not an attack vector.

Affected software

How to mitigate CVE-2026-63531

External References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-63531
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-63531

Related Security Bulletins

• Multiple vulnerabilities in Microsoft Office