CVE-2026-58644

CRITICAL CISA KEV
ACT NOW Priority: 1.56 BB Relevance: 83/100
Published: 2026-07-14 Modified: 2026-10-28 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Auth No Interaction Conf. Impact Integ. Impact

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: None
S: Unchanged
C: High
I: High
A: High

Description

Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.

CISA Known Exploited Vulnerability

Vendor / Product Microsoft — SharePoint
Date Added 2026-07-16
Remediation Due 2026-07-19
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58644 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-58644

Bug Bounty Relevance

83 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity
✓ No user interaction
✓ Known exploited (KEV)

CVSS Score

9.8 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C

EPSS — Exploitation Probability

15.87%
Raw Score 0.158730
Percentile 96.9%
Date 2026-10-28

Intelligence Sources

kev ref →
mitre ref →