MSRC_CVE-2026-21511

Vulnerability from csaf_microsoft - Published: 2026-02-10 00:00 - Updated: 2026-02-11 00:00
Summary
Microsoft Outlook Spoofing Vulnerability

Notes

Additional Resources
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle
Disclaimer
The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.
Customer Action
Required. The vulnerability documented by this CVE requires customer action to resolve.
To clipboard 

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      },
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          "text": "Microsoft",
          "title": "Assigning CNA"
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          "title": "Is the Preview Pane an attack vector for this vulnerability?"
        },
        {
          "category": "faq",
          "text": "An attacker could exploit this spoofing vulnerability by using a specially crafted email to trigger an outbound NTLM authentication attempt to an attacker\u2011controlled server, resulting in credential disclosure.",
          "title": "How could an attacker exploit this vulnerability?"
        },
        {
          "category": "faq",
          "text": "Yes. Customers should apply all updates offered for the software installed on their systems. If multiple updates apply, they can be installed in any order.",
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            "confidentialityImpact": "HIGH",
            "environmentalsScore": 0.0,
            "exploitCodeMaturity": "UNPROVEN",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "remediationLevel": "OFFICIAL_FIX",
            "reportConfidence": "CONFIRMED",
            "scope": "UNCHANGED",
            "temporalScore": 6.5,
            "userInteraction": "NONE",
            "vectorString": "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",
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          "details": "Spoofing"
        },
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          "category": "exploit_status",
          "details": "Publicly Disclosed:No;Exploited:No;Latest Software Release:Exploitation More Likely"
        }
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      "title": "Microsoft Outlook Spoofing Vulnerability"
    }
  ]
}


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Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.