Page generated: 09 Nov 2026, 04:58 UTC
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CVE-2026-55040

Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.

CVSS 9.1 (CRITICAL) KEV: KNOWN CATALOG

Attention and evidence

HYPE SCORE
0.0/10
REALITY · THREAT PRIORITY
8.7/10
General review priority; not probability

Evidence confidence: Exploitation recorded

Why this priority?
  • Recorded exploitation baseline: +7.00
  • Technical severity: CVSS 9.1: +1.36
  • Fresh EPSS: 69.54%: +0.35

General review priority, not probability, victim count or asset-specific risk. A range covers missing CVSS/EPSS inputs within the current evidence state.

Sources: 26 documents and public datasets.

Hype components

Headline sample (25%)
0/100
Press, 30 days (60%)
0/100
Grounded branding (15%)
0/100
HYPE TOTAL0/100

Sources and documents

The Hacker News
Press · 22 Sep 2026, 07:00 · SharePoint Flaw Initially Listed as Spoofing by Microsoft Enables Authenticated RCE - The Hacker News
Arctic Wolf
Press · 21 Sep 2026, 23:04 · Recommendations for CVE-2026-55040 - Arctic Wolf
Help Net Security
Press · 04 Sep 2026, 07:00 · September 2026 Patch Tuesday forecast: All we need is more time - Help Net Security
LinkedIn
Press · 26 Aug 2026, 07:00 · WARNING: Critical Microsoft SharePoint Exploit Chain Discovered - LinkedIn
BleepingComputer
Press · 26 Aug 2026, 07:00 · Hackers target Microsoft SharePoint RCE chain with PoC exploit - BleepingComputer
See all 26 source documents
Cybersecurity Dive
Press · 25 Aug 2026, 07:00 · Researchers warn about chained SharePoint sequence - Cybersecurity Dive
Rapid7
Press · 24 Aug 2026, 07:00 · Technical Analysis of Microsoft SharePoint Remote Code Execution vulnerability CVE-2026-63520 - Rapid7
CyberSecurityNews
Press · 19 Aug 2026, 07:00 · CISA Adds Microsoft SharePoint Weak Authentication Vulnerability to KEV List - CyberSecurityNews
The Hacker News
Press · 19 Aug 2026, 07:00 · Critical macOS, SharePoint, vCenter, and Microsoft IKE Flaws Under Active Exploitation - The Hacker News
Help Net Security
Press · 13 Aug 2026, 07:00 · Attackers exploit critical SharePoint flaw after PoC goes public (CVE-2026-55040) - Help Net Security
LinkedIn
Press · 13 Aug 2026, 07:00 · Hackers Move Quickly To Exploit Critical Microsoft SharePoint Authentication Bypass - LinkedIn
Security Affairs
Press · 13 Aug 2026, 07:00 · SharePoint CVE-2026-55040 Comes Under Attack Following Public Exploit - Security Affairs
The Hacker News
Press · 13 Aug 2026, 07:00 · Attackers Exploit SharePoint Authentication Bypass After Public PoC Release - The Hacker News
BleepingComputer
Press · 12 Aug 2026, 07:00 · Hackers leverage new Microsoft SharePoint exploit in attacks - BleepingComputer
SecurityWeek
Press · 12 Aug 2026, 07:00 · SharePoint Vulnerability Exploited Shortly After PoC Release - SecurityWeek
The Hacker News
Press · 11 Aug 2026, 07:00 · Researchers Disclose AI-Assisted SharePoint Exploit Chain Reaching Unauthenticated RCE - The Hacker News
Rapid7
Press · 11 Aug 2026, 07:00 · CVE-2026-63520: Microsoft SharePoint Remote Code Execution (FIXED) - Rapid7
Rapid7
Press · 11 Aug 2026, 07:00 · Microsoft SharePoint JWT Token Authentication Bypass Technical Analysis (CVE-2026-55040) - Rapid7
Resecurity
Press · 18 Jul 2026, 07:00 · From Web Request to Domain Compromise: Understanding the July 2026 SharePoint Attacks - Resecurity
SecurityWeek
Press · 17 Jul 2026, 07:00 · Fresh SharePoint Vulnerability Exploited Soon After Disclosure - SecurityWeek
LinkedIn
Press · 16 Jul 2026, 07:00 · WARNING: Threat Actors Exploit Multiple Microsoft SharePoint Flaws - LinkedIn
Cybersecurity Dive
Press · 15 Jul 2026, 07:00 · CISA warns that multiple vulnerabilities in SharePoint are under exploitation - Cybersecurity Dive
Field Effect
Press · 15 Jul 2026, 07:00 · Microsoft July 2026 Patch Tuesday Addresses Exploited SharePoint Vulnerabilities - Field Effect
Zero Day Initiative - Blog
Press · 14 Jul 2026, 17:56 · The July 2026 Security Update Review
Rapid7
Press · 14 Jul 2026, 07:00 · CVE-2026-55040: Microsoft SharePoint JWT Token Authentication Bypass (FIXED) - Rapid7
Cisco Talos Blog
Press · 14 Jul 2026, 07:00 · Microsoft Patch Tuesday for July 2026 — Snort rules and prominent vulnerabilities - Cisco Talos Blog

Score evolution

● Hype   ● Reality

Earlier evidence-support scores are retained in history; this chart shows only the current priority definition.

First record: hype 0.0 · reality 8.7 (2026-11-02 15:14). The curve appears once the score changes.

Public exploit evidence

0

Public exploit entries / repo candidates

Evidence context and dated references

Reality is general threat/review priority, combining observed exploitation, CVSS severity and fresh EPSS. Evidence confidence is separate. This is not calibrated risk, a victim count or an asset-specific assessment. A range reflects missing numeric inputs.

Evidence in context

Confidence in exploitation evidence
Exploitation recorded
Priority basis
Recorded exploitation; CVSS 9.1; EPSS 69.5%
Attention, last 30 days
0 distinct story titles; 0 press documents; 0 publisher domains.
Technical potential
network access, no prior privileges, no user interaction.
Observed activity
Exploitation recorded in CISA KEV.
Known scale
Not quantified.
Evidence confidence basis
Trusted exploitation confirmation

Score evaluated: 2026-11-05 14:00:15.521283+00:00 · EPSS snapshot: 2026-11-05T12:03:04Z

Source event timeline
First press mention
14 Jul 2026, 07:00
Published
14 Jul 2026, 17:09
Added to the CISA KEV catalog
18 Aug 2026, 00:00
Latest press mention
22 Sep 2026, 07:00
Score calculated
05 Nov 2026, 14:00