Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2026-24858

FortiWeb Authentication Bypass

Fortinet / FortiWeb · affected before *

Watch CVE-2026-24858 Browse KEV feed
Severity
CVSS 9.8 · Critical
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
85.8%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-24858 is an unauthenticated vulnerability affecting Fortinet FortiWeb and 5 other products. An Authentication Bypass Using an Alternate Path or Channel vulnerability [CWE-288] vulnerability in Fortinet...

Is it exploited?

Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is confirmed. Listed in CISA KEV. Also confirmed by third-party sources.

Who is affected?

Fortinet / FortiWeb affected before *.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

FortiWeb Authentication Bypass

An Authentication Bypass Using an Alternate Path or Channel vulnerability [CWE-288] vulnerability in Fortinet FortiAnalyzer 7.6.0 through 7.6.5, FortiAnalyzer 7.4.0 through 7.4.9, FortiAnalyzer 7.2.0 through 7.2.11, FortiAnalyzer 7.0.0 through 7.0.15, FortiManager 7.6.0 through 7.6.5, FortiManager 7.4.0 through 7.4.9, FortiManager 7.2.0 through 7.2.11, FortiManager 7.0.0 through 7.0.15, FortiNAC-F 7.6.3 through 7.6.5, FortiOS 7.6.0 through 7.6.5, FortiOS 7.4.0 through 7.4.10, FortiOS 7.2.0 through 7.2.12, FortiOS 7.0.0 through 7.0.18, FortiProxy 7.6.0 through 7.6.4, FortiProxy 7.4.0 through 7.4.12, FortiProxy 7.2.0 through 7.2.15, FortiProxy 7.0.0 through 7.0.22, FortiWeb 8.0.0 through 8.0.3, FortiWeb 7.6.0 through 7.6.6, FortiWeb 7.4.0 through 7.4.11 may allow an attacker with a FortiCloud account and a registered device to log into other devices registered to other accounts, if FortiCloud SSO authentication is enabled on those devices.

Siemens Affected
RUGGEDCOM APE1808
Before *
Fortinet Affected
FortiWeb
Through 8.0.3 Through 7.6.6 Through 7.4.11
Fortinet Affected
FortiNAC-F
Through 7.6.5
Fortinet Affected
FortiOS
Through 7.6.5 Through 7.4.10 Through 7.2.12 Through 7.0.18
Fortinet Affected
FortiAnalyzer
Through 7.6.5 Through 7.4.9 Through 7.2.11 Through 7.0.15
Fortinet Affected
FortiProxy
Through 7.6.4 Through 7.4.12 Through 7.2.15 Through 7.0.22
Fortinet Affected
FortiManager
Through 7.6.5 Through 7.4.9 Through 7.2.11 Through 7.0.15
Published
27 Jan 2026
Exploitation Reported
01 Jun 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

cisa ios edge

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CVE

Recorded 01 Jun 2026

A trusted third party reported exploitation.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
CVE First 2026-06-01 10:49 UTC
CISA 2026-06-02 14:03 UTC
Tenable Blog 2026-08-26 13:00 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

No detection artifacts or sensor request patterns are available for this CVE yet.

Check back as sensor telemetry and scanner integrations are updated.

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

9.8 Critical

Potential damage if exploited. Separate from whether attackers are using it.

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

EPSS

85.8%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Authentication Bypass Using an Alternate Path or Channel CWE-288

Recent mention · SOCRadar

Agentic Ransomware: From Human-Operated to AI-Operated Attacks

Agentic Ransomware: From Human-Operated to AI-Operated Attacks Ransomware has always needed a human involved somewhere: an affiliate navigating a network by hand, or at minimum, a person who wrote the script the malware

Read full advisory

All Mentions

Recent mention · SOCRadar

Agentic Ransomware: From Human-Operated to AI-Operated Attacks

SOCRadar · 15 Sep 2026

Agentic Ransomware: From Human-Operated to AI-Operated Attacks Ransomware has always needed a human involved somewhere: an affiliate navigating a network by hand, or at minimum, a person who wrote the script the malware

Recent mention · Tenable Blog

Edge infrastructure under siege: what two independent datasets reveal about who's exploiting your perimeter

Tenable Blog · 26 Aug 2026

A joint Tenable-SentinelOne analysis of 93 CVE-actor attribution pairs reveals that both state-sponsored actors and cybercriminals independently converge on the same edge infrastructure. Special thanks to SentinelOne® Incident Readiness & Response for their contributions to this publication.It is the shared attack surface where state-sponsored threat actors and financially motivated criminal groups independently converge — not the province of a single adversary category, and not exclusively a nation-state problem, despite two years of headlines about China-nexus actors targeting Ivanti,...

Timeline

From disclosure to observed exploitation

  1. 13:00 UTC

    KEV confirmed by Tenable Blog

    Exploitation attested by an external source

  2. 14:03 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  3. 10:49 UTC

    Added to Previdian KEV Feed

    High-confidence, third-party attested exploitation

  4. 19:18 UTC

    CVE published

    Vulnerability disclosed publicly

  5. 15:11 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-24858

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2026-24858",
  "confidence": "Confirmed",
  "cvss_score": 9.8,
  "cvss_estimated": false,
  "epss_score": 0.85796,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}