Description

A flaw was found in popt. This vulnerability allows an attacker to provide specially crafted configuration content to a host, which, when loaded, can lead to a small memory corruption issue. This occurs because of an error in how the `poptConfigFileToString` function reallocates memory for buffers. Successful exploitation could result in heap metadata corruption, potentially causing the affected process to become unavailable (denial of service).

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "2.5",
  "pubDate": "2026-09-01T02:16:57.647Z",
  "pubdate": "2026-09-01T02:16:57.647Z",
  "executiveSummary": "A memory corruption vulnerability exists in the popt library, specifically within the poptConfigFileToString function.\nThe vulnerability is categorized as a heap-based memory corruption issue resulting from improper buffer reallocation logic.\nAn attacker can exploit this flaw by supplying a specially crafted configuration file to an application utilizing the popt library.\nSuccessful exploitation leads to heap metadata corruption, which typically results in an application crash and subsequent Denial of Service (DoS) of the affected process.\nThis vulnerability impacts any system or application that parses external or untrusted configuration files via the affected popt function.\nNo specific authentication or elevated privileges are strictly required if the application processes attacker-controlled configuration files.\nThe primary risk implication is service instability and potential service unavailability, necessitating urgent attention for systems relying on popt for configuration parsing.",
  "technicalDetails": "The root cause of the vulnerability resides in the memory management logic of the poptConfigFileToString function within the popt library. During the processing of configuration content, the function is responsible for dynamic buffer allocation and subsequent resizing (reallocation) to accommodate the configuration data.\nThe vulnerability occurs when the reallocation logic fails to correctly handle buffer boundary conditions or pointer updates during memory expansion. Specifically, if the reallocation process does not maintain proper synchronization or fails to account for the internal structure of the heap during the copy operation, it induces heap metadata corruption.\nThe attack flow begins when an attacker provides a maliciously crafted configuration file or data stream to a target process that invokes poptConfigFileToString to parse it. As the parser processes the input, it triggers the flawed reallocation routine. When the memory manager attempts to reallocate the buffer for the configuration string, the erroneous logic causes the heap manager to overwrite or mismanage heap chunk headers.\nThe payload consists of configuration content designed to trigger a specific memory growth pattern that exposes the flawed reallocation logic. By providing carefully sized or structured input, the attacker forces the library to perform a realloc operation that results in a write-out-of-bounds or invalid pointer arithmetic involving the heap metadata.\nUpon successful corruption of the heap metadata, the next heap operation (such as a subsequent malloc, free, or realloc) triggered by the application will likely detect the inconsistency, leading to a SIGABRT or similar crash mechanism. In some scenarios, this corruption can lead to undefined behavior, though the primary observed impact is an immediate Denial of Service (DoS) due to process termination.\nThe vulnerable component is explicitly the poptConfigFileToString function. Because this function is a core part of the configuration parsing lifecycle, any application that delegates the reading of configuration files to popt is potentially susceptible if it processes untrusted input files. There are no specific version numbers provided, implying the vulnerability exists in versions currently utilizing the flawed implementation of this function. Exploitation does not require authentication to the system itself, provided the attacker can influence the configuration file that the target application reads."
}