Critical

CISA Adds Three Known Exploited Vulnerabilities to Catalog

All CISA Advisories
Actively Exploited

Overview

The Cybersecurity and Infrastructure Security Agency (CISA) has added three vulnerabilities to its Known Exploited Vulnerabilities Catalog due to evidence that they are being actively exploited. The vulnerabilities include two related to Fortinet's FortiSandbox, identified as CVE-2026-25089 and CVE-2026-39808, both of which are OS command injection flaws. The third vulnerability, CVE-2026-58644, affects Microsoft SharePoint and involves the deserialization of untrusted data. These vulnerabilities present serious risks, especially to federal agencies, which are urged to prioritize their remediation as mandated by CISA’s Binding Operational Directive 26-04. While this directive applies specifically to federal civilian agencies, CISA encourages all organizations to adopt similar practices for managing vulnerabilities. Organizations are also invited to report any exploited vulnerabilities not currently listed in the KEV Catalog.

Key Takeaways

  • Active Exploitation: This vulnerability is being actively exploited by attackers. Immediate action is recommended.
  • Affected Systems: Fortinet FortiSandbox (CVE-2026-25089, CVE-2026-39808), Microsoft SharePoint (CVE-2026-58644)
  • Action Required: Federal agencies should prioritize rapid remediation of these vulnerabilities in publicly exposed assets.
  • Timeline: Newly disclosed

Original Article Summary

CISA has added three new vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog, based on evidence of active exploitation. CVE-2026-25089 Fortinet FortiSandbox OS Command Injection Vulnerability CVE-2026-39808 Fortinet FortiSandbox OS Command Injection Vulnerability CVE-2026-58644 Microsoft SharePoint Deserialization of Untrusted Data Vulnerability These types of vulnerabilities are frequent attack vectors for malicious cyber actors and pose significant risks to the federal enterprise. Binding Operational Directive (BOD) 26-04: Prioritizing Security Updates Based on Risk establishes vulnerability management requirements for Federal Civilian Executive Branch (FCEB) agencies. BOD 26-04 reinforces the importance of the KEV Catalog and requires federal agencies to prioritize rapid remediation of high-risk vulnerabilities, specifically those identified by Common Vulnerabilities and Exposures (CVEs) listed in CISA’s KEV Catalog on publicly exposed assets that grant total control of the asset post-exploitation, while deferring action for lower-risk vulnerabilities. BOD 26-04 further establishes basic expectations for when agencies must check whether threat actors compromised the system before the patch was applied. While BOD 26-04 applies only to FCEB agencies, CISA encourages all organizations to adopt risk-based vulnerability management and prioritize remediation of KEV Catalog vulnerabilities. CISA will continue to add vulnerabilities to the catalog that meet the specified criteria. Aware of an exploited vulnerability not currently listed in the KEV Catalog? Submit it for potential addition through CISA’s KEV Nomination Form. Potential KEV additions must have a CVE ID, evidence of exploitation, and clear mitigation guidance.

Impact

Fortinet FortiSandbox (CVE-2026-25089, CVE-2026-39808), Microsoft SharePoint (CVE-2026-58644)

Exploitation Status

This vulnerability is confirmed to be actively exploited by attackers in real-world attacks. Organizations should prioritize patching or implementing workarounds immediately.

Timeline

Newly disclosed

Remediation

Federal agencies should prioritize rapid remediation of these vulnerabilities in publicly exposed assets. Organizations are encouraged to apply patches or updates for Fortinet FortiSandbox and Microsoft SharePoint as soon as they become available to mitigate risks. Checking for prior compromises before applying patches is also recommended.

Additional Information

This threat intelligence is aggregated from trusted cybersecurity sources. For the most up-to-date information, technical details, and official vendor guidance, please refer to the original article linked below.

Related Topics: This incident relates to CVE, Microsoft, Fortinet, and 2 more.

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