Fortinet FortiMail Path Traversal Vulnerability (CVE-2026-104286) is being actively exploited, CISA warns
CISA added CVE-2026-104286 (Fortinet FortiMail) to its Known Exploited Vulnerabilities catalog on October 1, 2026, which means there is reliable evidence of exploitation in the wild. Fortinet FortiMail contains a path traversal and an improper neutralization of NULL byte or NULL character vulnerability that may allow an unauthenticated attacker to write arbitrary files on the underlying system via crafted HTTP or…
Excerpt from the primary source: CISA Known Exploited Vulnerabilities
Who is affected
Small businesses · Enterprises · Security professionals
Affected technology: FortiGate / FortiOS, FortiMail
Why it matters
CISA lists this as exploited in the wild. Unpatched FortiGate / FortiOS and FortiMail systems are exposed to active attacks now.
Automated: stated only from CISA listings and the exploitation evidence in the sources below.
What you should do · Act now
Treat this as an emergency. Identify every system running FortiGate / FortiOS and FortiMail, apply the vendor's fix or published mitigations immediately, and check for signs of compromise. Patching alone does not remove an attacker who already got in.
CISA's required action for CVE-2026-104286: "Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines." US federal civilian agencies must comply by October 4, 2026.
Automated guidance based on this story's classification. Check the linked advisories for specifics.
Sources
We link to original and authoritative sources. Headlines and excerpts belong to their publishers.
Government advisory
Original reporting
Related
US, Australia warn of latest Citrix vulnerability after NetScaler advisory
Citrix confirmed late on Friday that it was “tracking a newly observed issue” related to some customer-managed NetScaler deployments but claimed the problem was not connected to vulnerabilities reported last week that also caused alarm among cybersecurity experts.
New Dell System Update flaw lets hackers gain root privileges
Dell warned customers to patch a critical vulnerability in the System Update (DSU) command-line interface (CLI) deployment tool as soon as possible.
Apply the vendor's security update for the affected products.
Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability (CVE-2026-88779) is being actively exploited, CISA warns
CISA added CVE-2026-88779 (Citrix NetScaler) to its Known Exploited Vulnerabilities catalog on October 4, 2026, which means there is reliable evidence of exploitation in the wild. Citrix NetScaler ADC (formerly Citrix ADC) and Citrix NetScaler Gateway (formerly Citrix Gateway) contain an improper restriction of operations within the bounds of a memory buffer vulnerability that could allow for a denial of service.
CISA lists this as exploited in the wild. Unpatched NetScaler ADC / Gateway systems are exposed to active attacks now.
Treat this as an emergency.
Fortra Patches Critical Vulnerabilities in BoKS
The bugs could lead to authentication bypass, shell command execution, and memory corruption.
Apply the vendor's security update for the affected products.