CVE-2026-45659

Analyzed
Published: 22 May 2026, 22:04
Last modified:11 Aug 2026, 03:55

Vulnerability Summary

Overall Risk (default)
medium
37/100
CVSS Score
8.8 HIGH
v3.1 (cve.org)
EPSS Score
9.86% LOW
10% probability +0.74%
KEV
Listed
CISA
1 listing
Ransomware
Known Use
Public exploits
None found
Dark Web
Not detected

Timeline

22 May 2026, 22:04
Published
Vulnerability first disclosed
01 Jul 2026, 00:00
Added to CISA KEV
Microsoft SharePoint Server Deserialization of Untrusted Data Vulnerability
04 Jul 2026, 00:00
CISA Remediation Due
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
11 Aug 2026, 03:55
Last Modified
Vulnerability information updated

Description

Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.

CVSS Metrics

  • v3.1•HIGH•Score: 8.8CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
  • v3.1•HIGH•Score: 8.8CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Trends

Current EPSS score: 9.86%• Percentile: 95%

Techniques & Countermeasures

  • CWE-502•Deserialization of Untrusted Data

    The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

Affected Systems

  • microsoft•microsoft sharepoint enterprise server 2016

    ≥ 16.0.0, < 16.0.5552.1002

  • microsoft•microsoft sharepoint server 2019

    ≥ 16.0.0, < 16.0.10417.20128

  • microsoft•microsoft sharepoint server subscription edition

    ≥ 16.0.0, < 16.0.19725.20280

  • microsoft•sharepoint_server

    < 16.0.19725.20280 | 2016 | 2019

References (2)