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:

  • Cisco Critical Flaw Patched in WAN Software Solution

    August 19, 2020

    Cisco patched a critical flaw in its wide area network (WAN) software solution for enterprises, which if exploited could give remote, unauthenticated attackers administrator privileges. The flaw exists in Cisco Virtual Wide Area Application Services (vWAAS), which is software that Cisco describes as a “WAN optimization solution.” It helps manage business applications that are being leveraged ...

  • Researchers Warn of Flaw Affecting Millions of IoT Devices

    August 19, 2020

    Researchers are urging connected-device manufacturers to ensure they have applied patches addressing a flaw in a module used by millions of Internet-of-Things (IoT) devices. If exploited, researchers speculated that the flaw could allow attackers to knock out a city’s electricity or even overdose a medical patient. The vulnerability exists in a widely used Cinterion module, a ...

  • ‘EmoCrash’ Exploit Stoppered Emotet For 6 Months

    August 17, 2020

    A researcher was able to exploit a vulnerability in Emotet – effectively causing the infamous malware to crash and preventing it from infecting systems for six months. Emotet, which first emerged in 2014 and has since then evolved into a full fledged botnet that’s designed to steal account credentials and download further malware, mysteriously disappeared from ...

  • How Unsecure gRPC Implementations Can Compromise APIs, Applications

    August 17, 2020

    Enterprises are turning to microservice architecture to build future-facing applications. Microservices allow enterprises to efficiently manage infrastructure, easily deploy updates or improvements, and help IT teams innovate, fail, and learn faster. It also allows enterprises to craft applications that can easily scale with demand. Additionally, as enterprises switch architectures — jumping from the traditional monolithic to ...

  • Patch List: Adobe, Citrix, Intel, and vBulletin Vulns

    August 14, 2020

    Vulnerabilities expose enterprises’ systems to compromise. Now that many employees are working from home and operating devices outside the more secure office environments, the need to patch vulnerabilities as soon as they are discovered has become even more pressing. Aside from Microsoft, the following vendors also released patches recently: Adobe, Citrix, Intel, and vBulletin. We rounded ...

  • XCSSET Mac Malware: Infects Xcode Projects, Performs UXSS Attack on Safari, Other Browsers, Leverages Zero-day Exploits

    August 13, 2020

    Trend Micro has discovered an unusual infection related to Xcode developer projects. Upon further investigation, we discovered that a developer’s Xcode project at large contained the source malware, which leads to a rabbit hole of malicious payloads. Most notable in our investigation is the discovery of two zero-day exploits: one is used to steal cookies ...