CVE-2026-58097 in ppp
Summary
by MITRE • 08/26/2026
mp_SetEnddisc() copied a user-supplied PSN endpoint value without length validation, allowing a buffer overflow via the ppp(8) command interface.
A local user with access to the ppp(8) command interface can crash ppp(8) or potentially execute arbitrary code as root.
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Analysis
by VulDB Data Team • 08/26/2026
The vulnerability identified in the mp_SetEnddisc function represents a critical memory safety flaw within the Point-to-Point Protocol daemon, commonly referred to as ppp on Unix-like operating systems. This specific issue stems from an improper handling of user-supplied input during the processing of disc end points. Specifically, when the system receives a PSN endpoint value provided by a local user through the command interface, it proceeds to copy this data into a fixed-size buffer without performing any length validation or bounds checking. In software security terms, this is a classic instance of an out-of-bounds write operation where the destination buffer lacks sufficient capacity to hold the potentially oversized input, leading directly to memory corruption.
From a technical perspective, the absence of boundary checks allows an attacker who has access to the ppp command interface to inject data that exceeds the allocated stack or heap space associated with this function call. When the copy operation executes, it overwrites adjacent memory locations which may contain critical control data such as return addresses, frame pointers, or other metadata essential for program execution flow. This corruption can manifest in two primary ways depending on the specific memory layout and timing of the exploit. The most immediate consequence is a denial of service condition where the integrity of the process state is compromised, causing the ppp daemon to crash unexpectedly. Such crashes disrupt network connectivity services that rely on this daemon for managing point-to-point connections, thereby impacting system availability.
However, the severity escalates significantly when considering the potential for remote code execution or privilege escalation. Since the ppp daemon typically operates with elevated privileges, often running as root to manage network interfaces and routing tables successfully exploiting this buffer overflow allows an attacker to overwrite critical memory structures in a controlled manner. By carefully crafting the input payload, it is possible to manipulate the instruction pointer or function return address to redirect execution flow toward shellcode injected into the same buffer or adjacent memory regions. This would enable arbitrary code execution with root-level permissions, granting full control over the underlying operating system. The attacker can then install backdoors, exfiltrate sensitive data, pivot to other systems on the network, or modify system configurations to maintain persistent access.
This vulnerability aligns closely with Common Weakness Enumeration category CWE-120, which describes buffer copy without checking size limits, a fundamental flaw in C and C++ programming where developers fail to verify that input fits within the destination buffer. Furthermore, from an offensive security standpoint as defined by the MITRE ATT&CK framework, this exploit vector relates to techniques involving local privilege escalation and command execution via memory corruption. The attack requires local access initially but leverages the high-privilege context of the daemon to achieve broader system compromise. It highlights the risks associated with legacy network utilities that may not adhere to modern secure coding practices regarding input validation and memory management.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. The most effective solution is for vendors to release a patch that updates the mp_SetEnddisc function to include rigorous length validation before copying user-supplied data into fixed buffers. Developers should implement bounds checking mechanisms such as using strlcpy instead of strcpy or similar unsafe functions, ensuring that the copy operation never exceeds the allocated buffer size. Additionally, employing compiler-based security features like stack canaries, Address Space Layout Randomization (ASLR), and Non-Executable Stack (NX) bits can mitigate the impact by making exploitation more difficult even if a vulnerability exists. System administrators should also restrict access to the ppp command interface to trusted users only, applying principle of least privilege to limit the attack surface available to potential local attackers until patches are applied.