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01 Record

CVE-2026-21260

Microsoft Outlook Spoofing Vulnerability

HighPUBLISHEDCNA: microsoft
CNA base score7.5 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C

02 Description

Microsoft Outlook Spoofing Vulnerability

03 Exploitation and scoring

Exploitation
Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
SSVC decision
  • ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
  • AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
  • Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
1.52% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 74.3% of scored records. A rank, not a probability.
NVD base score
7.5 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD analysis status
Analyzed. NVD last modified this record on 2026-06-17.
Red Hat severity
No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2026-02-10 17:51Z8 MO AGO
Last updated
2026-08-19 16:25Z2 MO AGO
Reserved
2025-12-11
Assigning CNA
microsoft
Record state
PUBLISHED
Severity
High (CVSS 7.5)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C
Weaknesses
  • CWE-200Exposure of Sensitive Information to an Unauthorized ActorClass
Data version
5.2
Document digest
b076af05bca416e7f30af9568bba3c5977a623d52b0ff3dd02f38a7ca4ac2424

05 Affected products

VendorProductVersionsPlatforms
MicrosoftMicrosoft 365 Apps for Enterprise16.0.1 to < https://aka.ms/OfficeSecurityReleases32-bit Systems, x64-based Systems
MicrosoftMicrosoft Office 201919.0.0 to < https://aka.ms/OfficeSecurityReleases32-bit Systems, x64-based Systems
MicrosoftMicrosoft Office LTSC 202116.0.1 to < https://aka.ms/OfficeSecurityReleases32-bit Systems, x64-based Systems
MicrosoftMicrosoft Office LTSC 202416.0.0 to < https://aka.ms/OfficeSecurityReleases32-bit Systems, x64-based Systems
MicrosoftMicrosoft Outlook 201616.0.0.0 to < 16.0.5539.100232-bit Systems, x64-based Systems
MicrosoftMicrosoft SharePoint Enterprise Server 201616.0.0 to < 16.0.5539.1002x64-based Systems
MicrosoftMicrosoft SharePoint Server 201916.0.0 to < 16.0.10417.20097x64-based Systems
MicrosoftMicrosoft SharePoint Server Subscription Edition16.0.0 to < 16.0.19127.20518x64-based Systems

06 References