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cve recordhighexploited in the wild3 of 3 cataloguesransomwareexploit reported

CVE-2026-45659

Microsoft · SharePoint Server · Microsoft SharePoint Server Deserialization of Untrusted Data Vulnerability

Published · Added to CISA KEV
CVSS8.8
Severityhigh
WeaknessCWE-502
EPSS2.7%85.8th percentile
Exploited3 KEV sources
Ransomware useKnown
Federal fix dueJul 4, 2026

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

patch window

Called exploited 40 days after disclosure.

Measured from the CVE publication date to the earliest of 3 KEV catalogues that list it.

The life of this vulnerability

  1. CVE published
  2. First KEV listing40d
  3. Last sighting50d

Gaps are compressed to equal steps. The elapsed time is printed under each.

Which catalogues call it exploited

Sources3 of 3
Listings differ by0 d
Strongest claimconfirmed

3 catalogues list it. CIRCL aggregates the others and is shown but not counted.

Public exploitation evidence

7 public reports collected from VulnCheck and CIRCL, first on Jul 1, 2026. Each links to its original source. We have not verified them.

Description

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

Required action (CISA)

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.

References

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Our coverage of CVE-2026-45659

CVE-2026-55040critical

Attackers Exploit SharePoint Authentication Bypass After Public PoC Release

Threat actors are actively exploiting a critical Microsoft SharePoint vulnerability, identified as CVE-2026-55040, according to recent reports. This exploitation campaign began shortly after a proof-of-concept (PoC) exploit for the flaw was publicly released. The vulnerability is described as a security feature bypass, enabling unauthenticated attackers to impersonate legitimate users within…

CVE-2008-4128high

July 2026 CVE Landscape

Cybersecurity researchers identified 85 high-impact vulnerabilities in July 2026 that require urgent remediation, marking a 44% increase from the previous month. Of these, 36 were assigned a "Very Critical" risk score by Insikt Group. The vulnerabilities affected products from 61 vendors, with Microsoft accounting for approximately 12% of the total.