CVE entry · CVE-2026-58644
CVE-2026-58644: Microsoft SharePoint Deserialization of Untrusted Data Vulnerability
Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.
- Actively exploited: added to CISA’s KEV catalog on July 16, 2026.
- Use by ransomware: not established so far.
- Remediation deadline for US federal agencies: July 19, 2026.
- CERT-FR alert CERTFR-2026-ALE-008 of July 22, 2026.
Description from CISA’s KEV catalog.
CERT-FR alerts and notices
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CERTFR-2026-ALE-008Multiples vulnérabilités dans Microsoft Sharepoint (22 juillet 2026)
What to do
- Check whether your estate includes Microsoft SharePoint, including internet-facing devices.
- Apply the vendor’s patch or mitigations (references below). Failing that, isolate the product or stop using it, as CISA requires of US federal agencies.
- An exploited vulnerability has often been used before it was fixed: look for signs of compromise, especially on internet-facing devices.
References
- Vendor advisory or reference cited by CISA (msrc.microsoft.com)
- NVD entry (NIST)
- CISA KEV catalog
Other Microsoft vulnerabilities
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Microsoft Windows Command Injection Vulnerability
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Microsoft SharePoint Code Injection Vulnerability
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Microsoft Windows Heap-Based Buffer Overflow Vulnerability
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Microsoft Windows Link Following Vulnerability
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Microsoft SQL Server Remote Code Execution Vulnerability
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Microsoft SharePoint Weak Authentication Vulnerability