CVE-2026-78503
mediumpriority · track · 26EPSS 0.009 · 60 %ileDENLUSEPSS · scored 2026-10-27
Out-of-bounds read in Microsoft Office Word allows an unauthorized attacker to disclose information over a network.
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
A vendor fix is available.
- FixedMicrosoft 365 Apps for Enterprise for 32-bit Systemsmsrc_csaf
16.0.20326.20138:Security Update:https://docs.microsoft.com/en-us/officeupdates/office365-proplus-security-updates
https://docs.microsoft.com/en-us/officeupdates/office365-proplus-security-updates - FixedMicrosoft 365 Apps for Enterprise for 64-bit Systemsmsrc_csaf
16.0.20326.20138:Security Update:https://docs.microsoft.com/en-us/officeupdates/office365-proplus-security-updates
https://docs.microsoft.com/en-us/officeupdates/office365-proplus-security-updates - FixedMicrosoft Office 2019 for 32-bit editionsmsrc_csaf
16.0.10417.20207:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft Office 2019 for 64-bit editionsmsrc_csaf
16.0.10417.20207:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft Office 365 for Macmsrc_csaf
16.113.26091433:Security Update:https://www.microsoft.com/en-us/microsoft-365/mac/microsoft-365-for-mac?msockid=35f9adb0e74b61392038b90de6fe608c
https://www.microsoft.com/en-us/microsoft-365/mac/microsoft-365-for-mac?msockid=35f9adb0e74b61392038b90de6fe608c - FixedMicrosoft Office LTSC 2021 for 32-bit editionsmsrc_csaf
16.0.14334.20906:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft Office LTSC 2021 for 64-bit editionsmsrc_csaf
16.0.14334.20906:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft Office LTSC 2024 for 32-bit editionsmsrc_csaf
16.0.17932.20976:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft Office LTSC 2024 for 64-bit editionsmsrc_csaf
16.0.17932.20976:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft Office LTSC for Mac 2021msrc_csaf
16.113.26091433:Security Update:https://go.microsoft.com/fwlink/p/?linkid=831049
https://go.microsoft.com/fwlink/p/?linkid=831049 - FixedMicrosoft Office LTSC for Mac 2024msrc_csaf
16.113.26091433:Security Update:https://go.microsoft.com/fwlink/p/?linkid=831049
https://go.microsoft.com/fwlink/p/?linkid=831049 - FixedMicrosoft Word 2016 (32-bit edition)msrc_csaf
16.0.5569.1000:Security Update:https://support.microsoft.com/help/5002923
https://support.microsoft.com/help/5002923 - FixedMicrosoft Word 2016 (64-bit edition)msrc_csaf
16.0.5569.1000:Security Update:https://support.microsoft.com/help/5002923
https://support.microsoft.com/help/5002923
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (77)
Products and version ranges known to be affected.
- Microsoft SharePoint Server Subscription Editionall versionscert_bundDEcpe:/a:microsoft:sharepoint:server_subscription_edition
- Microsoft Skype for Business Server 2015 CU13all versionscert_bundDEcpe:/a:microsoft:skype:for_business_server_2015_cu13
- Microsoft Skype for Business Server 2019 CU8all versionscert_bundDEcpe:/a:microsoft:skype:for_business_server_2019_cu8
- Microsoft Skype for Business Server Subscription Edition CU1all versionscert_bundDEcpe:/a:microsoft:skype:for_business_server_subscription_edition_cu1
advisories (3)
Vendor and ecosystem advisories describing this.
- NCSC-2026-0352Kwetsbaarheden verholpen in Microsoft OfficeNL2026-09-08csaf · ncsc_nlNL
Microsoft heeft 114 kwetsbaarheden verholpen in diverse Office producten.
- WID-SEC-W-2026-3234Microsoft Office Produkte: Mehrere SchwachstellenDeutsch2026-09-08csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in verschiedenen Microsoft Office Produkten, Microsoft Office Online Server, Microsoft 365 Apps, Microsoft SharePoint, Microsoft Teams und Microsoft Skype ausnutzen, um erhöhte Berechtigungen zu erlangen, um Code auszuführen, um Informationen offenzulegen und um den Nutzer zu täuschen.
- msrc_CVE-2026-78503Microsoft Office Word Information Disclosure Vulnerability2026-09-08csaf · msrc_csafUS
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle
sources
Which sources assert this record, and when.
references (1) nvd
External citations — patches, advisories, analysis.
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-78503PatchVendor Advisory
Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.
Free scan