CVE-2026-45659
Published: 22 May 2026
Summary
CVE-2026-45659 is a high-severity Deserialization of Untrusted Data (CWE-502) vulnerability in Microsoft Sharepoint Server. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 29.6% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
Threat & Defense at a Glance
Threat & Defense Details
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Penetration testing supplies malicious serialized objects, detecting unsafe deserialization and supporting corrective actions.
Evaluation of untrusted data handling (deserialization testing) reveals unsafe processing, which the required remediation process addresses.
Untrusted serialized data can be deserialized and observed inside the chamber, blocking gadget-chain exploitation outside the sandbox.
Validates or rejects untrusted serialized data before deserialization occurs.
Identifies and blocks malicious code introduced through deserialization of untrusted data at system boundaries.
Integrity verification of serialized information can detect tampering before deserialization occurs.
Provenance of associated data allows detection of untrusted sources before deserialization or processing occurs.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Deserialization RCE in internet-facing SharePoint server directly enables remote exploitation of a public-facing application.
NVD Description
Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.
Deeper analysisAI
Automated synthesis unavailable for this CVE.
Details
- CWE(s)
- OWASP Top 10 Web 2025
Affected Products
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-31518