CVE-2026-26144 Microsoft Excel Information Disclosure Vulnerability
An attacker can exploit a cross-site scripting flaw in Microsoft Excel to disclose sensitive information over the network.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-26144?
CVE-2026-26144 is a high-severity cross-site scripting vulnerability in Microsoft 365 Apps, published on 10 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office Excel allows an unauthorized attacker to disclose information over a network.
Weakness: CWE-79
Which versions are affected by CVE-2026-26144?
It affects 1 product.
Products include Microsoft 365 Apps.
How do I fix CVE-2026-26144?
No fix has been published for CVE-2026-26144 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-26144 being exploited?
There is no known exploitation of CVE-2026-26144 in the wild and no public exploit code.
Other vulnerabilities in Microsoft 365 Apps
- CVE-2024-21413 Microsoft Outlook Improper Input Validation
- CVE-2023-23397 Microsoft Office Outlook Privilege Escalation
- CVE-2024-38189 Microsoft Project Remote Code Execution Vulnerability
- CVE-2023-35311 Microsoft Outlook Security Feature Bypass
- CVE-2026-21514 Microsoft Office Word Reliance on Untrusted Inputs in a Security Decision
Sources
Also known as GHSA-39m5-6xwx-6qjf.