CVE-2026-94654 in Thrift
Summary
by MITRE • 10/02/2026
Loop with unreachable exit condition ('infinite loop') vulnerability in Apache Thrift python bindings.
This issue affects Apache Thrift: before 0.25.0.
Users are recommended to upgrade to version 0.25.0, which fixes the issue.
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Analysis
by VulDB Data Team • 10/02/2026
The identified vulnerability within the Apache Thrift Python bindings constitutes a logical flaw characterized by an infinite loop resulting from an unreachable exit condition. This type of defect typically arises when a control flow structure, such as a while or for loop, lacks a proper termination criterion due to incorrect variable updates, flawed boundary checks, or unexpected input states that prevent the loop counter or iterator from reaching its stopping point. In the context of networked application frameworks like Apache Thrift, which facilitates cross-language service development and remote procedure calls, such loops can be triggered during the serialization or deserialization process when processing specific malformed or edge-case data structures. The absence of a mechanism to break out of this loop means that the executing thread remains perpetually occupied in computational activity without progressing toward completion.
From an operational perspective, the primary impact of this vulnerability is a denial of service against the affected application instance. Since Python threads are often bound to operating system threads or managed by interpreters with limited concurrency models depending on the deployment environment, an infinite loop effectively consumes available CPU resources indefinitely. This resource exhaustion can lead to significant latency for other legitimate requests processed by the same server process, potentially causing timeouts and service degradation for end-users. In worst-case scenarios where the application does not implement robust isolation between request handlers, a single maliciously crafted RPC call could crash or hang the entire worker thread pool, rendering the Thrift-based service unavailable until manual intervention is required to restart the affected processes.
This vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-835, which describes loops that do not terminate due to unreachable exit conditions. It also relates closely to CWE-400 regarding uncontrolled resource consumption, as the infinite execution directly leads to CPU exhaustion. In terms of adversary tactics and techniques, this flaw could be leveraged within the MITRE ATT&CK framework under T1499, Endpoint Denial of Service, specifically through persistent endpoint denial via service exhaustion or volume-based attacks if the loop is triggered repeatedly by automated scripts targeting multiple endpoints simultaneously. The lack of timeout mechanisms in certain parsing routines exacerbates the risk, allowing attackers to sustain resource depletion over extended periods without detection by standard health checks that rely on response times rather than internal thread states.
Mitigation strategies primarily involve upgrading to Apache Thrift version 0.25.0 or later, where this logical error has been corrected through code changes that ensure proper loop termination logic is enforced during data processing. For organizations unable to immediately upgrade, implementing runtime safeguards such as application-level timeouts for RPC calls can help mitigate the impact by forcibly terminating long-running operations before they exhaust system resources. Additionally, deploying web application firewalls or API gateways with request rate limiting and payload size restrictions may reduce the likelihood of triggering this specific code path in production environments. Regular security audits focusing on input validation and loop boundary conditions are recommended to prevent similar logical flaws from being introduced during future development cycles within any software relying on complex serialization logic.