CISA: Fortinet Releases Guidance to Address Ongoing Exploitation of Authentication Bypass Vulnerability CVE-2026-24858


Newly disclosed vulnerability Common Vulnerabilities and Exposures (CVE)-2026-24858 [Common Weakness Enumeration (CWE)-288: Authentication Bypass Using an Alternate Path or Channel] allows malicious actors with a FortiCloud account and a registered device to log in to separate devices registered to other users in FortiOS, FortiManager, FortiWeb, FortiProxy, and FortiAnalyzer, if FortiCloud single sign on (SSO) is enabled on devices.

Users are vulnerable to CVE-2026-24858 even if they updated Fortinet devices to address previously disclosed FortiCloud SSO bypass vulnerabilities CVE-2025-59718 and CVE-2025-59719 [CWE-347: Improper Verification of Cryptographic Signature]. CVE-2025-59718 and CVE-2025-59719 affect FortiOS, FortiWeb, FortiProxy, and FortiSwitch Manager, and allow malicious actors to bypass the SSO login authentication via a crafted Security Assertion Markup Language (SAML) message.

Read more…
Source: U.S. Cybersecurity and Infrastructure Security Agency


Sign up for the Cyber Security Review Newsletter
The latest cyber security news and insights delivered right to your inbox


Related:

  • Critical Citrix Bug Puts 80,000 Corporate LANs at Risk

    December 26, 2019

    Digital workspace and enterprise networks vendor Citrix has announced a critical vulnerability in the Citrix Application Delivery Controller (ADC) and Citrix Gateway. If exploited, it could allow unauthenticated attackers to gain remote access to a company’s local network and carry out arbitrary code execution. The Citrix products (formerly the NetScaler ADC and Gateway) are used for ...

  • Apple opens public bug bounty program, publishes official rules

    December 20, 2019

    Apple has formally opened its bug bounty program today to all security researchers, after announcing the move earlier this year in August at the Black Hat security conference in Las Vegas. Until today, Apple ran an invitation-based bug bounty program for selected security researchers only and was accepting only iOS security bugs. Starting today, the company will accept vulnerability ...

  • Unit 42 Discovers 13 New Vulnerabilities Across Microsoft and Adobe Products

    December 19, 2019

    Palo Alto Networks’ Unit 42 threat researchers have been credited with discovering six new vulnerabilities addressed by the Adobe Product Security Incident Response Team (PSIRT) as part of its December Adobe Security Bulletin APSB19-55 security updates. Additionally, seven new “important” rated vulnerabilities were addressed by the Microsoft Security Response Center (MSRC) as part of its September, October and November ...

  • DDoS Attacks and IoT Exploits: New Activity from Momentum Botnet

    December 16, 2019

    Trend Micro recently found notable malware activity affecting devices running Linux, a platform that has battled numerous issues just this year. Further analysis of retrieved malware samples revealed that these actions were connected to a botnet called Momentum (named for the image found in its communication channel). We found new details on the tools and techniques ...

  • Mirai Variant ECHOBOT Resurfaces with 13 Previously Unexploited Vulnerabilities

    December 13, 2019

    Since the discovery of the Mirai variant using the binary name ECHOBOT in May 2019, it has resurfaced from time to time, using new infrastructure, and more remarkably, adding to the list of vulnerabilities it scans for, as a means to increase its attack surface with each evolution. Unlike other Mirai variants, this particular variant stands out for the sheer ...

  • Windows 0-day exploit CVE-2019-1458 used in Operation WizardOpium

    December 11, 2019

    In November 2019, Kaspersky technologies successfully detected a Google Chrome 0-day exploit that was used in Operation WizardOpium attacks. During our investigation, we discovered that yet another 0-day exploit was used in those attacks. The exploit for Google Chrome embeds a 0-day EoP exploit (CVE-2019-1458) that is used to gain higher privileges on the infected machine as ...