THREATPORT/VULNERABILITY/CVE-2026-50522
CRITICAL SEVERITY
Actively Exploited · CISA KEV

CVE-2026-50522

Microsoft SharePoint Deserialization of Untrusted Data Vulnerability

CVSS
9.8
EPSS
21.0%
EPSS pct
97th
Exploited
Yes
Microsoft SharePoint contains a deserialization of untrusted data vulnerability which could allow an unauthorized attacker to execute code over a network.
Affected vendor
Microsoft
Affected product
SharePoint
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness type (CWE)
  • CWE-502 — Deserialization of Untrusted Data
Published
2026-07-14

Risk analysis

Based on its CVSS vector, this vulnerability is exploitable over the network, low attack complexity, requiring no privileges, no user interaction. Successful exploitation leads to high impact to confidentiality, high impact to integrity, high impact to availability.

Its EPSS score of 21.0% reflects a moderate probability of exploitation activity in the wild over the next 30 days, placing it above 97% of all scored CVEs.

Known exploited — CISA remediation

Added to KEV: 2026-07-22
Remediate by: 2026-07-25
Ransomware use: Unknown

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.

Check your external exposure to CVE-2026-50522

  • Confirm whether Microsoft SharePoint is running on any internet-facing host or subdomain.
  • Match discovered service fingerprints against the version affected by CVE-2026-50522.
  • Prioritise remediation if the asset is public, business-critical, or near authentication/payment flows — this CVE is actively exploited.

How ThreatPort helps with CVE-2026-50522

ThreatPort's external attack surface scanner checks your internet-facing assets — agentlessly, from the outside in — for the exposed services and versions that CVE-2026-50522 affects, then prioritises the finding by real risk using CISA KEV and FIRST.org EPSS.

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