CVE-2026-106447 in StableLib
Summary
by MITRE • 10/06/2026
StableLib is a stable library of useful TypeScript and JavaScript code. Prior to 2.0.4, the @stablelib/cbor decoder recursively processes nested CBOR arrays, maps, and tags through _decodeValue() without enforcing a maximum nesting depth. A sufficiently deep structure exhausts the JavaScript call stack, causing a decoding exception and potentially terminating an uncaught request worker or process. This issue is fixed in version 2.0.4.
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Analysis
by VulDB Data Team • 10/07/2026
The vulnerability identified within StableLib versions prior to 2.0.4 represents a critical resource exhaustion flaw stemming from the absence of depth limiting mechanisms during the parsing of Concise Binary Object Representation data. The @stablelib/cbor module, designed for efficient serialization and deserialization in TypeScript and JavaScript environments, implements a recursive decoding strategy via its _decodeValue function. This approach allows the library to traverse complex nested structures such as arrays, maps, and tagged items with ease but fails to impose any constraints on the recursion depth. In standard software engineering practices, recursive algorithms processing untrusted or semi-trusted input must include safeguards against infinite or excessively deep recursion to prevent stack overflow conditions. The lack of such a boundary check transforms this utility into an attack vector for Denial of Service scenarios.
From a technical perspective, JavaScript engines like V8 maintain a call stack that tracks active function invocations. Each recursive call adds a new frame to this stack, consuming memory and processing resources. When the CBOR payload contains deeply nested structures exceeding the engine's default or configured maximum call stack size, the interpreter throws an uncaught exception. This results in the immediate termination of the current execution context. In server-side environments using Node.js, where request handlers often run on single-threaded event loops or within worker threads, such a crash can lead to process instability. If not properly isolated by external orchestration tools like PM2 or Kubernetes liveness probes, this could result in service downtime and availability loss for downstream consumers relying on the StableLib integration.
The operational impact of this vulnerability is primarily centered around Availability, aligning with the CIA triad's focus on maintaining system uptime and accessibility. An attacker can craft a malicious CBOR payload featuring extreme nesting levels to trigger the stack overflow condition remotely or locally depending on where the library is utilized. This constitutes an Uncontrolled Recursion flaw, formally categorized under CWE-675 in the Common Weakness Enumeration database. The attack vector allows for efficient resource consumption with minimal effort from the adversary, as even moderately sized payloads can achieve deep nesting due to the compact nature of CBOR encoding compared to text-based formats like JSON.
In terms of threat modeling and adversarial simulation, this vulnerability maps directly to techniques observed in real-world attacks where attackers aim to disrupt service availability rather than compromise data integrity or confidentiality. Specifically, it aligns with MITRE ATT&CK technique T1496 Resource Hijacking under the sub-technique of Denial of Service via resource exhaustion. While not a traditional crypto-graphic failure, the misuse of recursive parsing without bounds is a common pattern in parser vulnerabilities that leads to system instability. Security teams should recognize this as a classic input validation failure where structural constraints are ignored during data ingestion phases.
Mitigation strategies for organizations utilizing StableLib involve immediate version upgrades to 2.0.4 or later, which implements proper depth limiting logic within the decoder. For environments unable to patch immediately due to dependency conflicts, defensive coding practices should be adopted at the integration layer. This includes wrapping the decoding operation in try-catch blocks to handle exceptions gracefully without crashing the host process, and implementing input size limits or pre-validation steps that reject excessively complex structures before they reach the parser. Additionally, monitoring for uncaught exception logs can serve as an early warning system for potential exploitation attempts targeting this specific weakness.