Threats / Fortinet / CVE-2026-24858
CVE-2026-24858
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Fortinet Multiple Products vulnerability
Fortinet products contain an authentication bypass in FortiCloud SSO that allows attackers with valid FortiCloud accounts to access devices registered to other accounts.
Verdict
Today item — known-exploited.
An attacker with a FortiCloud account can exploit an alternate authentication channel to bypass access controls and log into FortiAnalyzer, FortiManager, FortiOS, or FortiProxy instances registered to other organizations, provided SSO is enabled.
CISA KEV Yes · 2026-01-275EPSS 0.85844 (verify live)6CVSS 9.43CISA SSVC Exploitation: active · Automatable: yes · Impact: total4
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
11 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-01-27).
Probability (EPSS)
EPSS 0.85844 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 9.4 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C) · Affected: Fortinet, Multiple Products. Confirm exact fixed builds in the vendor advisory.CVSS — CNA-assigned (CVE.org), version 3.1, set at disclosure.
Weakness (CWE)
Mapped to CWE-288 Auth Bypass via Alternate Path — weakness family: Authentication.CWE — CNA-assigned (CVE.org); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: yes · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog the same day the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I register a FortiCloud account and identify target devices registered to other accounts with SSO enabled.
Business
Unauthorized access to security infrastructure across customer boundaries creates immediate breach risk.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I use my valid FortiCloud credentials to authenticate through the alternate channel to access a target device.
Business
Attacker gains administrative or user-level access to security appliances managing other organizations' networks.
3
Lateral reach — past segmentation narrative 3
Attacker
I pivot from the compromised device to extract configuration, logs, or credentials for lateral movement.
Business
Sensitive security telemetry and network architecture details are exposed across multiple customer environments.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05