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CVE-2025-3935 affects ConnectWise ScreenConnect versions 25.2.3 and earlier. The issue involves ASP.NET Web Forms ViewState handling: if the ASP.NET machine keys used to protect ViewState are compromised, an attacker can craft a malicious ViewState payload and submit it to the ScreenConnect web application, resulting in server-side code execution. The vendor states the root cause is platform-level ASP.NET ViewState behavior rather than ScreenConnect-specific cryptographic logic, but ScreenConnect was exposed to the risk through its dependency on ViewState. ConnectWise indicates that ScreenConnect 2025.4 disables ViewState and removes the product’s dependency on it.
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What an attacker gets, and what they’ve been doing with it.
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Patch, then assume compromise.
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
32 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A previously exploited ScreenConnect vulnerability that was used to steal secret machine keys from a ScreenConnect server.
An improper authentication vulnerability in ScreenConnect (CVE-2025-3935) that enables ViewState code injection attacks, exploited in a breach attributed to a suspected nation-state actor.
A deserialization vulnerability in ASP.NET ViewState within ConnectWise ScreenConnect that can be exploited to compromise affected environments; it was added to CISA’s KEV, indicating real-world exploitation.
An authentication bypass vulnerability in ConnectWise ScreenConnect that can enable unauthorized remote access to management consoles.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.