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Full vulnerability report · 2026
CVE-2026-24858High confidence

Fortinet Multiple Products Authentication Bypass Using an Alternate Path or Channel Vulnerability

Fortinet · Multiple Products

Official source articles: Siemens SSA-975644 ↗ · Fortinet FG-IR-26-060 ↗. Check the applicable product and release in the original source.

9.4CriticalCVSS 3.1
Recommended action
Patch only the product branches with a verified fix

CISA confirms exploitation in the wild and lists 2026-01-30 as the remediation due date. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityCriticalOperational priority:Critical, unchanged from published severity.unchanged

Evidence used

  • CISA confirms exploitation in the wild.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 85.80% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Fortinet Multiple Products and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
SSA-975644 · CSAF 2.0 · revision 2 · finalSiemens ProductCERTSSA-975644: Multiple Vulnerabilities in Fortigate NGFW on RUGGEDCOM APE1808 Devices
1 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • RUGGEDCOM APE1808
Summary
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, 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 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.
Remediation
Update Fortigate NGFW to V7.4.11 or later version. Contact customer support to receive patch and update information
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-4712

CISA KEV mirrored by ENISA

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.

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 27 Jan 2026. Evidence sources: cisa_kev.
ENISA score
9.4 · CVSS 3.1
Advisory evidence
5 linked advisory records
Explicit mitigation evidence

Only statements that explicitly mention a fix, patch, update, workaround or mitigation are shown here.

  • csaf_ncscnl · NCSC-2026-0079Kwetsbaarheden verholpen in Siemens producten
  • csaf_ncscnl · NCSC-2026-0041Kwetsbaarheid verholpen in Fortinet producten
Recommended actionPatch only the product branches with a verified fix

CISA confirms exploitation in the wild and lists 2026-01-30 as the remediation due date. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
01

What, why and how

Fortinet FortiAnalyzer, FortiManager, FortiOS, and FortiProxy contain an authentication bypass using an alternate path or channel that could 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.

What

Fortinet FortiAnalyzer, FortiManager, FortiOS, and FortiProxy contain an authentication bypass using an alternate path or channel that could 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.

Why

The product requires authentication, but the product has an alternate path or channel that does not require authentication.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may bypass an access boundary or take over an account.

What

Fortinet FortiAnalyzer, FortiManager, FortiOS, and FortiProxy contain an authentication bypass using an alternate path or channel that could 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.

Why

The product requires authentication, but the product has an alternate path or channel that does not require authentication.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may bypass an access boundary or take over an account.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2026-01-27.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Authentication Bypass Using an Alternate Path or Channel → bypass an access boundary or take over an account
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-288 ↗

CWE-288: Authentication Bypass Using an Alternate Path or Channel. The product requires authentication, but the product has an alternate path or channel that does not require authentication.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
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

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
Stolen credentials, tokens and legitimate administration functions may provide continued access without deploying a large custom toolset.
NetworkUnauthenticatedCWE-288CISA KEV
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-4712Known-exploited evidence recorded

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.

Official EUVD record ↗
BSI · German · WID-SEC-2026-0226Fortinet FortiAnalyzer, FortiManager, FortiOS und FortiProxy: Schwachstelle ermöglicht Erlangen von Administratorrechten

Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Fortinet FortiAnalyzer, Fortinet FortiManager, Fortinet FortiOS und Fortinet FortiProxy ausnutzen, um die Authentifizierung zu umgehen und so Administratorrechte zu erlangen.

Official advisory ↗
Canadian Centre for Cyber Security · English · AV26-059Fortinet security advisory (AV26-059) – Update 1

On January 27, 2026, Fortinet published a security advisory to address a critical vulnerability in the following products: Fortinet has stated that this vulnerability has been exploited in the wild. Fortinet has disabled FortiCloud SSO from devices running vulnerable versions. Clients must upgrade to the latest versions for the FortiCloud SSO authentication to function.

Official advisory ↗
Canadian Centre for Cyber Security · English · AL25-019AL25-019 - Vulnerabilities impacting Fortinet products - FortiCloud SSO Login Authentication Bypass - CVE-2025-59718 and CVE-2025-59719 - Update 2

An Alert is used to raise awareness of a recently identified cyber threat that may impact cyber information assets, and to provide additional detection and mitigation advice to recipients. The Canadian Centre for Cyber Security ("Cyber Centre") is also available to provide additional assistance regarding the content of this Alert to recipients as requested.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260128Security Bulletin 28 Jan 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 28 Jan 2026, published on 28 January 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0097Vulnérabilité dans les produits Fortinet

Une vulnérabilité a été découverte dans les produits Fortinet. Elle permet à un attaquant de provoquer un contournement de la politique de sécurité. Fortinet indique que la vulnérabilité CVE-2026-24858 est activement exploitée.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-002112フォーティネットのFortiAnalyzer等の複数製品における代替パスまたはチャネルを使用した認証回避に関する脆弱性

Fortinet FortiAnalyzer 7.6.0から7.6.5、FortiAnalyzer 7.4.0から7.4.9、FortiAnalyzer 7.2.0から7.2.11、FortiAnalyzer 7.0.0から7.0.15、FortiManager 7.6.0から7.6.5、FortiManager 7.4.0から7.4.9、FortiManager 7.2.0から7.2.11、FortiManager 7.0.0から7.0.15、FortiOS 7.6.0から7.6.5、FortiOS 7.4.0から7.4.10、FortiOS 7.2.0から7.2.12、FortiOS 7.0.0から7.0.18、FortiProxy 7.6.0から7.6.4、FortiProxy 7.4.0から7.4.12、FortiProxy 7.2の全バージョン、FortiProxy 7.0の全バージョン、FortiWeb 8.0.0から8.0.3、FortiWeb 7.6.0から7.6.6、FortiWeb 7.4.0から7.4.11において、CWE-288に該当する代替パスまたはチャネルを使用した認証バイパスの脆弱性が存在します。この脆弱性により、FortiCloudアカウントおよび登録済みデバイスを持つ攻撃者が、FortiCloud SSO認証が有効になっている他のアカウントに登録されたデバイスにログインできる可能性があります。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6679Fortinet 제품 보안 업데이트 권고

FortiAnalyzer, FortiManager, FortiOS, FortiProxy, FortiWeb에서 발생하는 인증우회 취약점(CVE-2026-24858) [1][2]

Official advisory ↗
NCSC-NL · Dutch · NCSC-2026-0079Kwetsbaarheden verholpen in Siemens producten

Multiple Fortinet products including FortiAnalyzer, FortiManager, FortiOS, and FortiProxy have an authentication bypass vulnerability exploitable via FortiCloud SSO, allowing attackers with FortiCloud credentials to access other users' devices.

Official advisory ↗
NCSC-NL · Dutch · NCSC-2026-0041Kwetsbaarheid verholpen in Fortinet producten

A vulnerability in Fortinet's FortiAnalyzer, FortiManager, and FortiOS allows attackers with FortiCloud accounts to bypass authentication, leading to unauthorized access to registered devices when FortiCloud SSO is enabled.

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix availability varies by product
Affected
RUGGEDCOM APE1808
Fixed
Action
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
Workaround
A mitigation or workaround reference is available from the source linked below; validate it against the affected product and version.
04

Evidence and provenance

Published 27 Jan 2026 · Last source change 9 Jun 2026, 14:27 UTC · CWE-288 · Authentication Bypass Using an Alternate Path or Channel

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-4712
Product sourceVendor CSAF · Siemens ProductCERT
Remediation sourceVendor CSAF · Siemens ProductCERT
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. BlackTree coverageBlackTree article coverage changed from no BlackTree article to 1 BlackTree article.
    Before
    no BlackTree article
    After
    1 BlackTree article
    BlackTree editorial ↗
  2. Vendor guidanceAuthoritative vendor guidance changed: added remediation: fortiguard.fortinet.com/FG-IR-26-060; removed remediation: fortinet.com/analysis-of-sso-abuse-on-fortios.
    Before
    mitigation: fortinet.com/analysis-of-sso-abuse-on-fortios · remediation: fortinet.com/analysis-of-sso-abuse-on-fortios · vendor advisory: fortiguard.fortinet.com/FG-IR-26-060
    After
    mitigation: fortinet.com/analysis-of-sso-abuse-on-fortios · remediation: fortiguard.fortinet.com/FG-IR-26-060 · vendor advisory: fortiguard.fortinet.com/FG-IR-26-060
    psirt@fortinet.com ↗
  3. Affected versionsThe structured affected or fixed version information changed.
    Before
    8.0.0 ≤ 8.0.3; 7.6.0 ≤ 7.6.6; 7.4.0 ≤ 7.4.11; 7.6.3 ≤ 7.6.5; 7.6.0 ≤ 7.6.5; 7.4.0 ≤ 7.4.10; 7.2.0 ≤ 7.2.12; 7.0.0 ≤ 7.0.18 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    FortiWeb: 8.0.0 ≤ 8.0.3, 7.6.0 ≤ 7.6.6, 7.4.0 ≤ 7.4.11; FortiNAC-F: 7.6.3 ≤ 7.6.5; FortiOS: 7.6.0 ≤ 7.6.5, 7.4.0 ≤ 7.4.10, 7.2.0 ≤ 7.2.12, 7.0.0 ≤ 7.0.18; FortiAnalyzer: 7.6.0 ≤ 7.6.5, 7.4.0 ≤ 7.4.9, 7.2.0 ≤ 7.2.11, 7.0.0 ≤ 7.0.15; FortiProxy: 7.6.0 ≤ 7.6.4, 7.4.0 ≤ 7.4.12, 7.2.0 ≤ 7.2.15, 7.0.0 ≤ 7.0.22; FortiManager: 7.6.0 ≤ 7.6.5, 7.4.0 ≤ 7.4.9, 7.2.0 ≤ 7.2.11, 7.0.0 ≤ 7.0.15 · Fixed: Upgrade to upcoming FortiOS version 8.0.0 or above; Upgrade to FortiOS version 7.6.6 or above; Upgrade to FortiOS version 7.4.11 or above; Upgrade to FortiOS version 7.2.13 or above; Upgrade to FortiOS version 7.0.19 or above; Upgrade to upcoming FortiManager version 8.0.0 or above; Upgrade to FortiManager version 7.6.6 or above; Upgrade to FortiManager version 7.4.10 or above; Upgrade to FortiManager version 7.2.12 or above; Upgrade to FortiManager version 7.0.16 or above; Upgrade to FortiAnalyzer version 7.6.6 or above; Upgrade to FortiAnalyzer version 7.4.10 or above
    CNA ↗
  4. Remediation statusRemediation status changed from Mitigation available to Patch available.
    Before
    Mitigation available
    After
    Patch available
    psirt@fortinet.com ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-4712↗Vendor CSAF · Siemens ProductCERT · Siemens SSA-975644↗CISA KEV record↗CVE authority or vendor reference · Fortinet FG-IR-26-060↗Mitigation reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-24858 · cve.blacktree.nl