CVE-2025-23122 in Node.js
Summary
by MITRE • 05/19/2025
In Node.js, the `ReadFileUtf8` internal binding leaks memory due to a corrupted pointer in `uv_fs_s.file`: a UTF-16 path buffer is allocated but subsequently overwritten when the file descriptor is set. This results in an unrecoverable memory leak on every call. Repeated use can cause unbounded memory growth, leading to a denial of service.
Impact: * This vulnerability affects APIs relying on `ReadFileUtf8` on Node.js release lines: v20 and v22.
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Analysis
by VulDB Data Team • 05/19/2025
The vulnerability identified as CVE-2025-23122 represents a critical memory management flaw within Node.js's internal file system operations, specifically impacting the `ReadFileUtf8` binding mechanism. This issue manifests as a persistent memory leak that occurs with every invocation of file reading operations, fundamentally compromising system stability and resource utilization. The flaw resides in the underlying libuv library integration where UTF-16 path buffers are improperly handled during file descriptor assignment, creating a scenario where allocated memory becomes inaccessible and unrecoverable through normal garbage collection processes. The vulnerability affects Node.js versions v20 and v22, making it particularly concerning for production environments that rely on these release lines for their applications.
The technical root cause of this memory leak stems from a corrupted pointer manipulation within the `uv_fs_s.file` structure, where a UTF-16 encoded path buffer undergoes allocation but is subsequently overwritten when the file descriptor is established. This pointer corruption creates a memory access violation that prevents proper resource deallocation, resulting in continuous memory accumulation with each file read operation. The flaw operates at the system call level through libuv's file system abstraction, making it particularly insidious as it bypasses typical application-level memory management safeguards. This vulnerability directly maps to CWE-401: Improper Release of Memory and aligns with ATT&CK technique T1499.004: Endpoint Denial of Service, as the memory exhaustion directly leads to system resource depletion. The memory corruption specifically affects the file system operation pipeline where path strings are converted from UTF-16 to UTF-8 encoding, creating an intermediate state where memory references become invalid and unrecoverable.
The operational impact of CVE-2025-23122 extends far beyond simple performance degradation, as it creates an unbounded memory growth pattern that can quickly exhaust available system resources. Applications utilizing Node.js v20 or v22 that perform frequent file read operations will experience progressive memory consumption until system stability is compromised. This vulnerability is particularly dangerous in server environments where continuous file access is common, such as web servers, API endpoints, or data processing applications. The memory leak operates silently without throwing exceptions or generating error messages, making it difficult to detect during routine monitoring and testing phases. The denial of service potential becomes increasingly severe with prolonged system uptime, as memory fragmentation and accumulation can lead to complete system instability or application crashes. This vulnerability essentially transforms any Node.js application using affected APIs into a memory consumption threat, potentially affecting not only the targeted process but also neighboring applications sharing system resources.
Mitigation strategies for CVE-2025-23122 require immediate attention and comprehensive system hardening measures. The most effective approach involves upgrading to patched versions of Node.js v20 or v22, as official releases will contain corrected memory management routines for the `ReadFileUtf8` binding. Organizations should implement immediate patch management protocols to ensure all affected systems receive updates without delay. In environments where immediate upgrades are not feasible, temporary workarounds include limiting file access frequency, implementing application-level memory monitoring, and using alternative file reading mechanisms that bypass the vulnerable internal bindings. System administrators should deploy enhanced monitoring solutions to detect memory consumption patterns that indicate the presence of this vulnerability, as the leak may not be immediately apparent during normal operation. Additionally, implementing resource limits and memory constraints on Node.js processes can help mitigate the impact of unbounded memory growth. Security teams should also consider implementing runtime protection measures that can detect and potentially block malicious exploitation attempts targeting this specific vulnerability pattern, particularly in environments where applications cannot be immediately patched.