VulnerabilityAnalyzed
CVE-2026-21511
Deserialization of untrusted data in Microsoft Office Outlook allows an unauthorized attacker to perform spoofing over a network.
HIGH 7.5EPSS 3.77%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (3.77%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Deserialization of untrusted data in Microsoft Office Outlook allows an unauthorized attacker to perform spoofing over a network.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 3.77% probability · 89th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-502
- Affected
- microsoft/365 apps · microsoft/office · microsoft/office long term servicing channel · microsoft/sharepoint server · microsoft/word
- Source
- secure@microsoft.com
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.