CVE-2026-104057 in Podgrab
Summary
by MITRE • 10/01/2026
Podgrab contains an unauthenticated denial-of-service vulnerability caused by unsynchronized concurrent access to shared maps (activePlayers and allConnections) in its WebSocket handler, where Wshandler and HandleWebsocketMessages goroutines read and write these maps without a mutex. A remote attacker can open multiple WebSocket connections to the /ws endpoint and send messages in a loop to trigger a Go runtime data race that crashes the process, causing a denial of service that requires operator intervention to restore service.
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Analysis
by VulDB Data Team • 10/01/2026
The vulnerability identified within Podgrab represents a critical concurrency flaw rooted in improper synchronization mechanisms for shared state management. Specifically, the application maintains two primary data structures, activePlayers and allConnections, which are accessed concurrently by multiple goroutines without adequate locking primitives. The WebSocket handler logic involves distinct execution paths where Wshandler and HandleWebsocketMessages operate simultaneously on these shared maps. In Go programming language environments, map access is not thread-safe by default; concurrent read-write operations to the same map will trigger a fatal runtime panic due to detected data races. This architectural oversight means that any interaction with the WebSocket endpoint can potentially destabilize the entire application process if timing conditions align such that one goroutine writes while another reads or writes concurrently.
From an operational perspective, this flaw enables a straightforward remote denial-of-service attack vector. An adversary does not require authentication to exploit this condition. By establishing multiple persistent WebSocket connections to the /ws endpoint and continuously transmitting messages in a rapid loop, the attacker can induce high-frequency concurrent access patterns that overwhelm the unsynchronized map operations. The resulting Go runtime panic causes immediate process termination. This leads to complete service unavailability for all users connected to or attempting to connect with Podgrab. Restoration of normal operation is not automatic; it necessitates manual intervention by system operators who must detect the crash, restart the application instance, and potentially investigate logs to confirm the nature of the failure before resuming standard operations.
This vulnerability aligns closely with Common Weakness Enumeration category CWE-362, which describes concurrent execution using shared resources with inadequate synchronization. The lack of mutex locks or other concurrency control mechanisms like channels for safe map access is a fundamental design error that violates basic principles of thread-safe programming in Go. Furthermore, the exploitation technique maps directly to MITRE ATT&CK tactic T1499, specifically Endpoint Denial of Service via resource exhaustion through application crashes. The attacker leverages the application's own logic against it by forcing an unrecoverable state rather than consuming excessive CPU or memory resources traditionally associated with DoS attacks.
Mitigation strategies must prioritize immediate code-level remediation to restore service integrity and prevent recurrence. Developers should implement mutex synchronization, such as sync.Mutex or sync.RWMutex, around all read and write operations on the activePlayers and allConnections maps within both Wshandler and HandleWebsocketMessages goroutines. Alternatively, refactoring the architecture to use channel-based communication for state transfer can eliminate shared mutable state entirely, adhering more closely to Go best practices for concurrency. In addition to code fixes, deploying runtime monitoring tools that detect panic conditions early can help minimize downtime by triggering automatic restarts or alerting operators promptly. Long-term solutions should include integrating race detection into the continuous integration pipeline using go test -race to catch such synchronization issues before deployment.