A double free and a NULL pointer dereference in Microsoft Office Excel allow remote code execution. An unauthenticated attacker can run code in the context of the user by sending a specially crafted Excel file, for example as an email attachment or download. Exploitation requires that the user opens the file, and Microsoft's CVSS rating is 8.8 (High). Microsoft 365 Apps, standalone Office releases and Office Online Server are affected.
Microsoft · 365 Apps
A heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code over a network. The attack requires a user to interact, for example by opening a crafted Excel file received by email or download. Microsoft rates the vulnerability as High (CVSS 3.1: 8.8), and CISA SSVC rates the technical impact as total.
Microsoft · Office Excel
A heap-based buffer overflow in Microsoft Office Excel, shipped in Microsoft 365 Apps, Office LTSC and Office for Mac editions, allows an unauthorized attacker to execute code over a network. Exploitation requires that a user opens a manipulated Excel file, for example one received by email or downloaded from the internet. Microsoft rates the flaw Critical, the CVSS base score is 8.8 (High), and no exploitation in the wild or public proof of concept has been reported.
Microsoft · Office Excel
Microsoft Office Excel in Microsoft 365 Apps, Office LTSC, Office for Mac and Office Online Server contains a heap-based buffer overflow (CWE-122). An unauthenticated remote attacker can execute code if a user opens a crafted Excel file, for example an email attachment or a downloaded file. Microsoft and NVD rate the flaw High (CVSS 8.8). No exploitation in the wild is known.
Microsoft · 365 Apps
An out-of-bounds write in Microsoft Excel, part of Microsoft Office and Microsoft 365 Apps, allows an unauthorized attacker to execute code over a network. The attack requires a user to act, for example by opening a malicious or downloaded spreadsheet, and no privileges are needed. The CVSS score is 8.8 (High) with a total impact on confidentiality, integrity and availability. Microsoft and CISA data show no known active exploitation and no public proof-of-concept exploit.
Microsoft · Excel (Microsoft 365 Apps / Office)
Microsoft Office Excel contains a stack-based buffer overflow (CWE-121) that affects Microsoft 365 Apps for Enterprise, Office LTSC 2024, Office 365 for Mac and Office LTSC for Mac 2021 and 2024. An attacker who persuades a user to open a crafted Excel file could execute code on the affected client. The attack needs no privileges but requires user interaction; the CVSS 3.1 base score is 8.8. Microsoft rates exploit code maturity as Unproven, and CISA SSVC records no exploitation.
Microsoft · Office Excel
Research and translation in progress – available shortly.
A use-after-free flaw (CWE-416) in Microsoft Office Excel allows remote code execution. An unauthenticated attacker can exploit it by sending a malicious Excel file, but a user must open the file (UI:R). The CVSS base score is 8.8 (High); Microsoft rates it Critical.
Microsoft · 365 Apps
A heap-based buffer overflow in Microsoft Office Excel allows a remote attacker to execute code. Exploitation requires that a user opens a crafted file, for example an email attachment or a downloaded file. The CVSS base score is 8.8 (High), and Microsoft released fixes on 13 October 2026.
Microsoft · Office Excel
A heap-based buffer overflow in Microsoft Office Excel, part of Microsoft 365 Apps and Office LTSC and Office for Mac editions, allows code execution over a network. Exploitation requires that a user opens a malicious Excel file, for example from an email attachment or a file-sharing link. The attacker can then run code with the rights of the user. CVSS 3.1 base score is 8.8 (NVD and Microsoft).
Microsoft · Office Excel
A heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code over a network. The attack requires that a user opens a crafted file, for example an Excel document received by email or downloaded from the web. Microsoft has released patches; the CVSS 3.1 base score is 8.8 (High), while Microsoft's page lists a Max Severity of Critical.
Microsoft · Office Excel
A out-of-bounds read in Microsoft Office Excel, part of Microsoft 365 Apps and Office, allows an unauthorized attacker to execute code over a network. Exploitation requires a user to take an action, such as opening a crafted Excel file. Server products in the affected list, including SharePoint Server Subscription Edition and Office Online Server, are also listed, and internet-published instances of these need priority attention. Microsoft's exploit maturity rating is unproven and no known exploitation was found at the time of research.
Microsoft · Office Excel
A heap-based buffer overflow in Microsoft Office Excel allows an unauthenticated attacker to execute code over a network. Exploitation requires that a user opens a crafted Excel file, for example one received by email or downloaded from the internet. Successful exploitation would give the attacker code execution with the rights of the user.
Microsoft · 365 Apps
A heap-based buffer overflow in Microsoft Office Excel, shipped in Microsoft 365 Apps, Office LTSC, Office for Mac and Office Online Server, allows an unauthorized attacker to execute code over a network. Exploitation requires that a user opens a crafted file, for example one received by email or downloaded from the web. Microsoft rates the flaw with CVSS 8.8; Microsoft and CISA data show no known exploitation in the wild at the time of publication.
Microsoft · Office Excel
A use-after-free vulnerability (CWE-416) in Microsoft Office Excel allows remote code execution. An unauthorized attacker can run code over the network if a user opens a crafted file, for example an email attachment or a download; no authentication is required. Microsoft rates the flaw Important (CVSS 8.8, high impact on confidentiality, integrity and availability). As of the records reviewed, no active exploitation and no public proof of concept are known.
Microsoft · Office Excel
A heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code over a network. No privileges are required, but a victim must open or process a crafted file, for example a spreadsheet received by email or download. The flaw is rated CVSS 8.8 (High) and Microsoft has released fixes in October 2026.
Microsoft · Office Excel
Microsoft Office Excel contains a stack-based buffer overflow (CWE-121) that allows an unauthenticated attacker to execute code over a network. Exploitation requires that a user interacts with the attack, most likely by opening a malicious spreadsheet. CVSS 3.1 rates it 8.8 (High), and CISA's SSVC data lists technical impact as total, with exploitation as none.
Microsoft · Office Excel
A double free weakness (CWE-415) in Microsoft Office Outlook allows an unauthenticated remote attacker to execute code. Microsoft rates it Critical (CVSS 9.8) and describes it as network-reachable with no privileges and no user interaction. According to the advisory text cited in the research notes, simply viewing a crafted message in the Reading Pane could trigger it, so email is the main attack path.
Microsoft · Office Outlook
A heap-based buffer overflow in Microsoft Office Excel allows an unauthenticated remote attacker to execute code over a network. The attack requires the victim to take an action, such as opening a manipulated spreadsheet from an email or download. Microsoft rates the flaw as Important with a CVSS 3.1 base score of 8.8, and no active exploitation is known.
Microsoft · Office Excel
A use-after-free weakness in Microsoft Office Excel allows an unauthorized attacker to execute code over a network. The attack requires that a user opens a malicious workbook, for example one received by email or downloaded from the internet. The CVSS base score is 8.8 (High), and the vendor rates the temporal score lower because exploit code maturity is unproven.
Microsoft · Office Excel
Microsoft Office Excel contains an integer underflow (CWE-191) that allows remote code execution. According to the CVSS vector, an unauthenticated attacker can exploit it over the network, but a user must interact with the crafted content, for example by opening a file. A successful attack could affect confidentiality, integrity and availability. Exploitation is not known and no public proof of concept was found.
Microsoft · Office Excel
A use-after-free vulnerability (CWE-416) in Microsoft Office Excel allows an unauthorized attacker to execute code over the network. Exploitation requires that a user opens or previews a manipulated spreadsheet, for example one delivered by email or download. The flaw is not an internet-facing service. Microsoft has released fixes with the October 2026 updates.
Microsoft · Office Excel
Research and translation in progress – available shortly.
Research and translation in progress – available shortly.
A stack-based buffer overflow (CWE-121) in Microsoft Office Excel allows an unauthenticated attacker to execute code over a network. User interaction is required (UI:R), so exploitation typically needs a victim to open a malicious spreadsheet received by email, download or web link. Microsoft rates the maximum severity as Critical, while NVD scores it CVSS 3.1 8.8 (High).
Microsoft · Excel (Microsoft 365 Apps, Office LTSC, Office Online Server)
