Cve 2026 28318

www.solarwinds.com • June 9, 2026

SolarWinds Serv-U is susceptible to specially crafted POST requests that crash the Serv-U service without authentication using Content-Encoding: deflate.

MITIGATION STEPS: SolarWinds suggests adding the following controls to your web access firewall.

SolarWinds Serv-U 15.5.4 and below

SolarWinds Serv-U 15.5.4 HF1

CVSS:7.5 /AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

The full story

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Active Exploitation of SolarWinds Serv-U Flaw CVE-2026-28318 The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has issued a warning regarding the active exploitation of a high-severity vulnerability in SolarWinds Serv-U, tracked as CVE-2026-28318. This flaw allows remote attackers to crash the Serv-U service using specially crafted POST requests without requiring authentication. The vulnerability stems from uncontrolled resource consumption and affects both Windows and Linux versions of Serv-U. SolarWinds released a hotfix (15.5.4 Hotfix 1) on June 4, 2026, to address this issue. CISA has added this CVE to its Known Exploited Vulnerabilities Catalog and mandated that all Federal Civilian Executive Branch agencies patch their servers by June 19, 2026. There are over 12,000 Serv-U servers exposed online, increasing the risk of exploitation. Administrators are advised to limit access to known addresses and block specific POST requests until the patch can be applied. 13 sources 73

Extracted Entities

Attack Types (1)

Zero-day Exploit

CVEs (1)

CVE-2026-28318