CISA Adds Actively Exploited SolarWinds Serv-U DoS Flaw to KEV Catalog

Summary

CISA has added a critical denial-of-service vulnerability in SolarWinds Serv-U software to its Known Exploited Vulnerabilities (KEV) catalog. The flaw, CVE-2026-28318, allows attackers to crash the service with specially crafted POST requests. Federal agencies are mandated to patch this vulnerability by June 19, 2026.

Full text

CISA Adds Actively Exploited SolarWinds Serv-U DoS Flaw to KEV Catalog Ravie LakshmananJun 06, 2026Vulnerability / Patch Management The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added a high-severity security flaw impacting SolarWinds Serv-U multi-protocol file server software to its Known Exploited Vulnerabilities (KEV) catalog, citing evidence of active exploitation. The vulnerability, tracked as CVE-2026-28318 (CVSS score: 7.5), is a denial-of-service (DoS) bug that causes the service to crash under certain conditions. CISA described it as an uncontrolled resource consumption vulnerability that results in a DoS condition. "SolarWinds Serv-U is susceptible to specially crafted POST requests that crash the Serv-U service without authentication using Content-Encoding: deflate," SolarWinds said in an advisory released earlier this week. The issue has been addressed in SolarWinds Serv-U version 15.5.4 HF1. As mitigations, it's advised to limit access to known addresses and block any request containing "content-encoding" since the vulnerable service does not require this functionality. There are currently no details on how the vulnerability is being exploited in real-world attacks, or who is behind them. It's also unclear how many internet-exposed Serv-U instances are compromised, if any. CISA has ordered Federal Civilian Executive Branch (FCEB) agencies to address the flaw by June 19, 2026. In the past, multiple flaws in Serv-U have been exploited by bad actors, including those associated with the Cl0p ransomware gang. Found this article interesting? Follow us on Google News, Twitter and LinkedIn to read more exclusive content we post. SHARE     Tweet Share Share Share SHARE  CISA, cybersecurity, denial of service, KEV Catalog, Patch Management, ransomware, Serv-U, SolarWinds, Vulnerability ⚡ Top Stories This Week Google June 2026 Android Update Patches 124 Flaws, One Actively Exploited Oracle WebLogic CVE-2024-21182 Added to KEV Catalog After Active Exploitation Dashlane Discloses Brute-Force Attack, Encrypted Vaults of Fewer Than 20 Users Downloaded Miasma Supply Chain Attack Compromises Red Hat npm Packages with Credential-Stealing Worm ⚡ Weekly Recap: New Linux Flaw, PAN-OS Exploit, AI-Powered Attacks, OAuth Phishing and More OpenAI Codex Authentication Tokens Stolen in codexui-android npm Supply Chain Attack PAN-OS GlobalProtect Authentication Bypass (CVE-2026-0257) Under Active Exploitation ChatGPhish Vulnerability Turns ChatGPT Web Summaries Into a Phishing Surface Attackers Use LLM Agent for Post-Exploitation After Marimo CVE-2026-39987 Exploit Threat Actors Exploit Critical FortiClient EMS Flaw to Deploy Credential Stealer Microsoft Slams Public Zero-Day Disclosures Amid GitHub Researcher Account Removal ThreatsDay Bulletin: Claude Security Plugin, Azure Priv-Esc, Kali365 MFA Bypass, FIFA Scams +15 More Malicious npm Package Stole Files From Claude AI User Directory via GitHub GlassWorm Malware Takedown Disrupts Developer Supply Chain Attack Infrastructure AI Chatbot Recommendations Redirect Users to Cryptojacking Malware Sites Microsoft Patches SharePoint RCE Flaw CVE-2026-45659 Across Server Versions ⭐ Featured Resources Your Employees Are Using AI in Ways You Can’t See – 2026 State of AI Report Learn How to Stop Attacks Before They Reach Your EDR – With PHASR Watch AI Turn Vulnerabilities Into Working Exploits in Minutes (See the Demo) [Guide] The Real Security Risks of Shadow AI (And Where You’re Exposed)

Indicators of Compromise

• cve — CVE-2026-28318

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