CVE-2025-26399

Deserialization of Untrusted Data in SolarWinds Web Help Desk. CISA confirmed attackers exploit it and added it to its Known Exploited Vulnerabilities catalog on 9 March 2026.

Product: SolarWinds Web Help Desk
Added to CISA's catalog: 9 March 2026
Federal fix-by date: 12 March 2026
Ransomware: Known to be used in ransomware
Vendor advisories: www.solarwinds.com/trust-center/security-advisories/cve-2025-26399
documentation.solarwinds.com/en/success_center/whd/content/release_notes/whd_12-8-7-hotfix-1_release_notes.htm
Sources: CISA’s catalog, NVD entry

CISA’s description.

SolarWinds Web Help Desk contain a deserialization of untrusted data vulnerability in AjaxProxy that could allow an attacker to run commands on the host machine.

CVE-2026-28318 Uncontrolled Resource Consumption, added 5 June 2026
CVE-2025-40536 Security Control Bypass, added 12 February 2026
CVE-2025-40551 Deserialization of Untrusted Data, added 3 February 2026

Every flaw CISA confirmed exploited in the last 30 days is on the exploit watch. This is not security advice. Check the vendor’s advisory before acting. From CISA’s catalog of 4 November 2026.

CVE-2025-26399

CISA’s description.

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