CVE-2026-91137 in Thrift
Summary
by MITRE • 10/02/2026
Improper validation of specified quantity in input, Allocation of resources without limits or throttling, Excessive Iteration vulnerability in Apache Thrift PHP bindings.
This issue affects Apache Thrift: before 0.25.0.
Users are recommended to upgrade to version 0.25.0, which fixes the issue.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 10/02/2026
The identified vulnerabilities within the Apache Thrift PHP bindings prior to version 0.25.0 represent significant security risks stemming from inadequate input validation and resource management mechanisms. These flaws primarily manifest as improper validation of specified quantities in user-supplied inputs, leading to potential denial-of-service conditions through excessive iteration or unbounded resource allocation. In distributed systems relying on Apache Thrift for inter-process communication, the framework serves as a critical bridge between client applications and backend services. When the PHP bindings fail to enforce strict limits on input parameters such as array sizes, string lengths, or loop counters, they create an attack surface where malicious actors can exploit these oversights to destabilize server processes. The core technical flaw lies in the absence of rigorous boundary checks before processing incoming data structures, allowing attackers to craft payloads that trigger infinite loops or consume disproportionate amounts of memory and CPU cycles during serialization and deserialization operations.
From a vulnerability classification perspective, this issue aligns with CWE-787: Out-of-bounds Write and CWE-400: Uncontrolled Resource Consumption. The improper validation of input quantities directly correlates to CWE-20: Improper Input Validation, where the application fails to verify that user inputs conform to expected formats or ranges before processing them. Furthermore, the allocation of resources without limits or throttling is a classic example of CWE-770: Allocation of Resources Without Limits or Throttling. These weaknesses are particularly dangerous in high-throughput environments because they can be triggered remotely via standard Thrift protocol calls. An attacker does not necessarily need authentication to exploit these flaws if the service exposes public endpoints, although authenticated attacks would allow for more targeted and persistent denial-of-service campaigns against specific user sessions or system resources.
The operational impact of exploiting these vulnerabilities is severe, primarily resulting in service degradation or complete unavailability through resource exhaustion. By sending specially crafted requests with excessively large quantities or triggering excessive iterations within the PHP bindings, an attacker can cause the server process to hang, crash, or become unresponsive to legitimate traffic. This denial-of-service condition disrupts business continuity and can lead to significant financial losses depending on the criticality of the affected service. Additionally, in some contexts, memory corruption resulting from out-of-bounds writes could potentially be leveraged for remote code execution, although the primary documented impact remains availability disruption. The lack of throttling means that even moderate volumes of malicious traffic can overwhelm system resources if not mitigated by external infrastructure controls such as rate limiting at the network or load balancer level.
To mitigate these risks, organizations must prioritize upgrading to Apache Thrift version 0.25.0 or later, which includes patches addressing these specific validation and resource management issues. In addition to software updates, defensive measures should include implementing strict input validation policies that enforce size limits on all incoming data structures before they are processed by the application logic. Network-level protections such as Web Application Firewalls (WAFs) can be configured to detect and block requests with unusually large payloads or high-frequency access patterns indicative of resource exhaustion attacks. It is also advisable to configure server-side timeouts and memory limits for PHP processes to ensure that even if an exploit attempt occurs, the impact is contained within a single process without taking down the entire service. Regular security assessments and penetration testing focused on input validation and resource consumption should be conducted to identify similar weaknesses in other components of the application stack.
The exploitation techniques associated with these vulnerabilities often fall under MITRE ATT&CK technique T1499: Endpoint Denial of Service, specifically sub-techniques involving resource exhaustion via excessive iteration or unbounded allocation. Adversaries may use automated tools to flood target systems with crafted Thrift requests designed to trigger the flawed validation logic in the PHP bindings. Defense-in-depth strategies are essential; relying solely on application-level fixes is insufficient given the potential for novel attack vectors targeting similar patterns in other libraries. Therefore, combining version upgrades with robust monitoring of system metrics such as CPU usage, memory consumption, and request latency can help detect exploitation attempts early. Security teams should also review their dependency management practices to ensure that third-party libraries like Apache Thrift are kept up-to-date with the latest security patches provided by upstream maintainers.