CVE-2026-66809
published 2026-08-11CVE-2026-66809: Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.
PriorityP427medium5.5CVSS 3.1
AVLACLPRLUINSUCHINAN
EPSS
0.28%
20.2th percentile
Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.
Affected
9 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| microsoft | microsoft_365_apps_for_enterprise | >= 16.0.1 < https://aka.ms/OfficeSecurityReleases | https://aka.ms/OfficeSecurityReleases |
| microsoft | microsoft_office_2019 | >= 19.0.0 < https://aka.ms/OfficeSecurityReleases | https://aka.ms/OfficeSecurityReleases |
| microsoft | microsoft_office_365_for_mac | >= 1.0.0 < 16.112.26081010 | 16.112.26081010 |
| microsoft | microsoft_office_ltsc_2021 | >= 16.0.1 < https://aka.ms/OfficeSecurityReleases | https://aka.ms/OfficeSecurityReleases |
| microsoft | microsoft_office_ltsc_2024 | >= 16.0.0 < https://aka.ms/OfficeSecurityReleases | https://aka.ms/OfficeSecurityReleases |
| microsoft | microsoft_office_ltsc_for_mac_2021 | >= 16.0.1 < 16.112.26081010 | 16.112.26081010 |
| microsoft | microsoft_office_ltsc_for_mac_2024 | >= 16.0.0 < 16.112.26081010 | 16.112.26081010 |
| microsoft | microsoft_word_2016 | >= 16.0.1 < 16.0.5565.1000 | 16.0.5565.1000 |
| microsoft | word | — | — |
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VulDB
Microsoft Office/Word up to Mac out-of-bounds (EUVD-2026-56752)
vuldb·2026-08-17·CVSS 5.5
CVE-2026-66809 [MEDIUM] Microsoft Office/Word up to Mac out-of-bounds (EUVD-2026-56752)
A vulnerability was found in Microsoft Office and Word up to Mac and classified as problematic. The impacted element is an unknown function. Executing a manipulation can lead to out-of-bounds read.
The identification of this vulnerability is CVE-2026-66809. The attack can only be executed locally. There is no exploit available.
A patch should be applied to remediate this issue.
GHSA
Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.
ghsa_unreviewed·2026-08-11
CVE-2026-66809 [MEDIUM] CWE-125 Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.
Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.
No detection rules found.
No public exploits indexed.
Rapid7
Patch Tuesday - August 2026
blogs_rapid7·2026-08-11·CVSS 7.2
CVE-2026-68821 [HIGH] Patch Tuesday - August 2026
Microsoft is publishing 421 vulnerabilities on August 2026 Patch Tuesday , including 236 vulnerabilities in Windows. This is lower volume than last month’s record-breaking behemoth, but still one of the largest Patch Tuesday totals ever. There is no reason to suppose that Patch Tuesday will ever return to the lower volumes we saw prior to 2026. Microsoft is aware of exploitation in the wild for one of the vulnerabilities published today, as well as public disclosure for two others, although the Notable CVEs section of the Security Update Guide omits one of these. As usual, browser vulns are not included in the Patch Tuesday count above, but unusually, Microsoft does not appear to have published any desktop browser security patches so far this month.
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Sans Isc
Microsoft Patch Tuesday August 2026, (Tue, Aug 11th)
blogs_sans_isc·2026-08-11·CVSS 7.8
CVE-2026-68820 [HIGH] Microsoft Patch Tuesday August 2026, (Tue, Aug 11th)
Microsoft Patch Tuesday August 2026
Published: 2026-08-11. Last Updated: 2026-08-11 17:54:49 UTC
by Renato Marinho (Version: 1)
0 comment(s)
This month we got patches for 418 vulnerabilities. Of these, 62 are critical, 1 is being exploited in the wild, and 2 were publicly disclosed as zero-days. Notable fixes include Windows privilege escalation, container tampering, and critical QUIC and DNS Server remote code execution bugs.
A few vulnerabilities worth mentioning:
Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability (CVE-2026-68820)
This Important-severity elevation of privilege vulnerability is listed by Microsoft as exploited in the wild but not publicly disclosed, and it has a CVSS score of 7.0. The flaw is a use-after-free issue in the Windows Ancil
2026-08-11
Published