Bug 2392939 (CVE-2025-52494)

Summary: CVE-2025-52494 aws: AdaCore AWS: Missing SSL handshake timeout can cause denial of service
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in AdaCore Web Server (AWS) where the server does not enforce a timeout during the SSL handshake when clients connect over HTTPS. Attackers can exploit this by sending specially crafted handshake messages that never complete, tying up the server's worker threads and preventing it from serving legitimate requests, resulting in a denial of service.
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Bug Depends On: 2402592, 2402593    
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Description OSIDB Bzimport 2025-09-03 18:01:20 UTC 
Adacore Ada Web Server (AWS) before 25.2 is vulnerable to a denial-of-service (DoS) condition due to improper handling of SSL handshakes during connection initialization. When a client initiates an HTTPS connection, the server performs the SSL handshake before assigning the connection to a processing slot. However, there is no specific timeout set for this phase, and the server uses the default socket timeout, which is effectively infinite. An attacker can exploit this by sending a malformed TLS ClientHello message with incorrect length values. This causes the server to wait indefinitely for data that never arrives, blocking the worker thread (Line) handling the connection. By opening multiple such connections, up to the server's maximum limit, the attacker can exhaust all available working threads, preventing the server from handling new, legitimate requests.