CVE-2026-70257 Heap-based buffer overflow in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network

Description

Heap-based buffer overflow in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.

Affected products and versions

Product	Affected versions	Fixed in
Microsoft 365 Apps for Enterprise 16.0	16.0.1 → latest	No fix stated
Microsoft Office LTSC 2021 16.0	16.0.1 → < 16.0.14334.20974	16.0.14334.20974
Microsoft Office LTSC 2024 16.0	16.0.0 → < 16.0.17932.21056	16.0.17932.21056

Other CVEs of Microsoft 365 Apps for Enterprise

The 931 CVEs of Microsoft 365 Apps for Enterprise →

CVE-2026-108455 Out-of-bounds read in Microsoft Office PowerPoint allows an unauthorized attacker to disclose information over a network 6.5 Medium CVE-2026-108454 Buffer over-read in Microsoft Office PowerPoint allows an unauthorized attacker to disclose information over a network 6.5 Medium CVE-2026-108453 Out-of-bounds read in Microsoft Office PowerPoint allows an unauthorized attacker to disclose information over a network 6.5 Medium CVE-2026-108450 Heap-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute code over a network 8.8 High