CISA KEV Critical Authentication

CVE-2026-24858 — Fortinet Multiple Products Authentication Bypass Using an Alternate Path or Channel Vulnerability

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.

Published Jan 27, 2026 · Updated Oct 13, 2026 · Sources: CISA Known Exploited Vulnerabilities, NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: fortinet

High

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

CISA KEV · Jan 27, 2026 Proofs of concept on GitHub · 5

How the score was calculated

Confirmed exploitation (CISA KEV)+35
Public exploit/PoC (github)+6
EPSS 85.8% (30-day exploitation probability)+15
Technical severity (critical)+10
Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Confirmed

CISA KEV, listed Jan 27, 2026

EPSS FIRST

85.8%

ahead of 100% of scored CVEs · Oct 14, 2026

Affects

Fortinet

Fortianalyzer and 6 more

CVSS base

9.8

Critical · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

Active

none · proof-of-concept · active

Automatable

Yes

can an attacker script the kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented mitigation — www.fortinet.com (NIST National Vulnerability Database)

CISA required action CISA

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

US federal deadline: Jan 30, 2026 — passed 258 day(s) ago

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Fortinet Fortianalyzer, Fortinet Fortimanager, Fortinet Fortinac-f…).
Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
Apply the documented mitigations until a definitive fix is available.
EPSS ahead of 100% of scored CVEs: prioritize it in the patch queue.
Search available logs for exploit probes matching the vulnerability class (authentication), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Fortinet	Fortianalyzer	≥ 7.0.0 and ≤ 7.0.15≥ 7.2.0 and ≤ 7.2.11≥ 7.4.0 and < 7.4.10≥ 7.6.0 and < 7.6.6	Vulnerable	NIST National Vulnerability Database
Fortinet	Fortianalyzer	≥ 7.6.0 and ≤ 7.6.5≥ 7.4.0 and ≤ 7.4.9≥ 7.2.0 and ≤ 7.2.11≥ 7.0.0 and ≤ 7.0.15	Vulnerable	CVE Program (cve.org) e CISA ADP
Fortinet	Fortimanager	≥ 7.4.0 and < 7.4.10≥ 7.6.0 and < 7.6.6≥ 7.0.0 and ≤ 7.0.15≥ 7.2.0 and ≤ 7.2.11	Vulnerable	NIST National Vulnerability Database
Fortinet	Fortimanager	≥ 7.6.0 and ≤ 7.6.5≥ 7.4.0 and ≤ 7.4.9≥ 7.2.0 and ≤ 7.2.11≥ 7.0.0 and ≤ 7.0.15	Vulnerable	CVE Program (cve.org) e CISA ADP
Fortinet	Fortinac-f	≥ 7.6.3 and ≤ 7.6.5	Vulnerable	CVE Program (cve.org) e CISA ADP
Fortinet	Fortinac-f	≥ 7.6.3 and < 7.6.6	Vulnerable	NIST National Vulnerability Database
Fortinet	Fortios	≥ 7.0.0 and ≤ 7.0.18≥ 7.2.0 and ≤ 7.2.12≥ 7.4.0 and ≤ 7.4.10≥ 7.6.0 and ≤ 7.6.5	Vulnerable	CVE Program (cve.org) e CISA ADP
Fortinet	Fortios	≥ 7.6.0 and < 7.6.6≥ 7.4.0 and < 7.4.11≥ 7.2.0 and ≤ 7.2.12≥ 7.0.0 and ≤ 7.0.18	Vulnerable	NIST National Vulnerability Database
Fortinet	Fortiproxy	≥ 7.2.0 and ≤ 7.2.15≥ 7.6.0 and ≤ 7.6.4≥ 7.4.0 and ≤ 7.4.12≥ 7.0.0 and ≤ 7.0.22	Vulnerable	NIST National Vulnerability Database
Fortinet	Fortiproxy	≥ 7.0.0 and ≤ 7.0.22≥ 7.2.0 and ≤ 7.2.15≥ 7.4.0 and ≤ 7.4.12≥ 7.6.0 and ≤ 7.6.4	Vulnerable	CVE Program (cve.org) e CISA ADP
Fortinet	Fortiweb	≥ 7.4.0 and ≤ 7.4.11≥ 7.6.0 and ≤ 7.6.6≥ 8.0.0 and ≤ 8.0.3	Vulnerable	NIST National Vulnerability Database
Fortinet	Fortiweb	≥ 8.0.0 and ≤ 8.0.3≥ 7.6.0 and ≤ 7.6.6≥ 7.4.0 and ≤ 7.4.11	Vulnerable	CVE Program (cve.org) e CISA ADP
Siemens	Ruggedcom Ape1808 Firmware	versions not specified by the source	Vulnerable	NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
9.8	CVSS 3.1	Critical	3.9	5.9	psirt@fortinet.com via NIST National Vulnerability Database
9.8	CVSS 3.1	Critical	—	—	GitHub, Inc. via GitHub Security Advisories
9.4	CVSS 3.1	Critical	—	—	fortinet via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (score shown at the top: psirt@fortinet.com)

Scoring entities (NIST, CNA, ADP) score independently; each score is shown with its origin. For prioritization we use 9.8 (psirt@fortinet.com via NIST National Vulnerability Database) as a conservative provisional reference — not a definitive official score.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-288 · Authentication Bypass Using an Alternate Path or Channel

Other CVEs with this weakness →

CISA KEV details CISA

CISA lists a CVE once it has evidence of exploitation against real targets.

Listed

Jan 27, 2026

Federal deadline

Jan 30, 2026

passed 258 day(s) ago

Ransomware use

Unknown

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.

Public exploits, PoCs and detection templates

Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.

Proofs of concept on GitHub

Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.

EPSS over time FIRST

Oct 12, 2026 → Oct 14, 2026 · 3 reading(s) · max 85.80%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Review authentication logs: logins without MFA, anomalous sessions and recently created accounts.
Hunt retroactively in logs from before Jan 27, 2026 (KEV listing): exploitation may have started earlier.

web/proxy/WAF logsnetwork IDS/IPSauthentication logs

Timeline

What happened to this CVE, newest first.

2026
Affected products added · fortinet/fortiweb, fortinet/fortinac-f, fortinet/fortios, fortinet/fortianalyzer, fortinet/fortiproxy, fortinet/fortiman
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
Fix documented
Oct 13, 2026 · NIST National Vulnerability Database
Affected products added · fortinet/fortianalyzer, fortinet/fortimanager, fortinet/fortinac-f, fortinet/fortiproxy, fortinet/fortiweb, fortinet/for
Oct 13, 2026 · NIST National Vulnerability Database
CVSS changed · 9.8
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 13, 2026 · NIST National Vulnerability Database
Added to CISA KEV (detected)
Oct 13, 2026 · CISA Known Exploited Vulnerabilities
Record created in this database
Oct 13, 2026 · CISA Known Exploited Vulnerabilities
CVE published
Jan 27, 2026 · fortinet
Added to CISA KEV catalog
Jan 26, 2026 · CISA

Source activity

Repeated readings are counted rather than listed.

2× References added · Oct 13, 2026 – Oct 13, 2026
1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

6 on the record

www.fortinet.com/blog/psirt-blogs/analysis-of-sso-abuse-on-fortios
Mitigation, Vendor Advisory, NIST National Vulnerability Database
fortiguard.fortinet.com/psirt/FG-IR-26-060
Vendor Advisory, NIST National Vulnerability Database
www.cisa.gov/known-exploited-vulnerabilities-catalog
US Government Resource, NIST National Vulnerability Database
github.com/advisories/GHSA-2x38-48vp-w23x
GitHub Security Advisories
cert-portal.siemens.com/productcert/html/ssa-975644.html
Third Party Advisory, NIST National Vulnerability Database
nvd.nist.gov/vuln/detail/CVE-2026-24858
GitHub Security Advisories

Elsewhere on this site

Fortinet
every CVE for this vendor

2026-01
what else CISA listed that month

Authentication
same class

CWE-288
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-23705 An Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')... 2d
High CVE-2026-23707 An Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')... 2d
Medium CVE-2026-23706 An Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')... 2d
Medium CVE-2026-106171 A improper neutralization of special elements used in an os command ('os command injection')... 2d
Low CVE-2026-106175 A Double Free vulnerability [CWE-415] vulnerability in Fortinet FortiOS 7.6.0 through 7.6.7,... 2d
High CVE-2025-46773 An Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')... 2d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-24858 is "Fortinet Multiple Products Authentication Bypass Using an Alternate Path or Channel Vulnerability", rated Critical. It affects Fortianalyzer (Fortinet); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 9.8 describes technical severity. EPSS 85.80% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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