CVE-2026-71979 in indi
Summary
by MITRE • 08/17/2026
INDI (Instrument Neutral Distributed Interface) indiserver through 2.2.4.2, fixed in commit 96bbd7f, contains a stack buffer overflow vulnerability that allows unauthenticated remote attackers to crash the daemon by sending malformed XML with mismatched tags whose names exceed 1024 bytes. Attackers can send a single TCP packet on port 7624 with mismatched XML tags to trigger an unbounded sprintf() write into a fixed 1024-byte stack buffer in MsgQueue.cpp, terminating the daemon and disrupting all active client and driver sessions.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 08/17/2026
The vulnerability identified within INDI indiserver versions up through 2.2.4.2 represents a critical security flaw rooted in improper input validation and unsafe memory management practices during XML parsing operations. Specifically, the defect resides in the MsgQueue.cpp module where the software processes incoming network data via TCP on port 7624. The core technical issue is an unbounded sprintf() call that writes user-supplied data into a fixed-size stack buffer of exactly one thousand and twenty-four bytes. When an attacker constructs a malicious XML payload containing mismatched tags with names exceeding this size limit, the function fails to check for boundary conditions before performing the write operation. This lack of bounds checking results in a classic stack-based buffer overflow, where excess data overwrites adjacent memory locations on the call stack, corrupting critical control structures such as return addresses or saved frame pointers.
From an operational perspective, this vulnerability is particularly severe due to its potential for remote exploitation without authentication and its direct impact on service availability. An unauthenticated attacker can trigger a denial of service condition by sending a single TCP packet with the malformed XML structure described above. The immediate consequence of triggering the buffer overflow is the termination or crash of the indiserver daemon process. Since INDI serves as a central hub for astronomical instrument control, crashing this daemon effectively disrupts all active client connections and driver sessions that rely on it for communication. This results in a complete loss of functionality for any observatory systems depending on the server, preventing users from controlling telescopes, cameras, or other peripheral devices until the service is manually restarted.
The technical classification of this flaw aligns with Common Weakness Enumeration (CWE) identifiers such as CWE-120 Buffer Copy without Checking Size of Input and CWE-787 Out-of-bounds Write on Stack. The exploitation vector involves sending a single network packet, which places it within the scope of remote code execution or denial of service via network interaction. In terms of MITRE ATT&CK framework mapping, this vulnerability facilitates initial access through unauthenticated network services and contributes to availability impact categories by causing system crashes. While the primary observed effect is a crash leading to denial of service, stack buffer overflows inherently carry the risk of arbitrary code execution if an attacker can precisely control the overwritten memory contents to redirect program flow, although in this specific instance, the immediate outcome described is daemon termination.
Mitigation strategies for this vulnerability involve both immediate patching and long-term architectural improvements. The most effective remediation is to upgrade INDI indiserver to a version later than 2.2.4.2 where commit 96bbd7f addresses the buffer overflow by implementing proper length checks before performing string copy operations. In environments where upgrading is not immediately feasible, network-level controls such as firewalls or intrusion prevention systems can be configured to inspect TCP traffic on port 7624 for abnormally large XML tag names or malformed structures, thereby blocking malicious packets before they reach the vulnerable application layer. Additionally, developers should enforce strict input validation policies that reject any XML elements with identifiers exceeding predefined length limits and replace unsafe functions like sprintf() with safer alternatives such as snprintf() which explicitly accept buffer size parameters to prevent overflows.