CVE-2026-95386 in Wireshark
Summary
by MITRE • 09/29/2026
TTL file parser infinite loop in 4.6.0 to 4.6.8 allows denial of service
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Analysis
by VulDB Data Team • 09/29/2026
The vulnerability identified as an infinite loop within the TTL (Terse Triple Language) file parser affects versions 4.6.0 through 4.6.8 of the affected software component. This flaw resides in the core parsing logic responsible for interpreting RDF data formatted according to the W3C Turtle standard, which is widely used in semantic web applications and knowledge graph implementations. The issue manifests when the parser encounters specific malformed or specially crafted input sequences that trigger a recursive loop without proper termination conditions or depth limits. Instead of failing gracefully with an error message indicating invalid syntax, the application enters a state where it continuously processes data within a single thread or process context, consuming available CPU cycles indefinitely until system resources are exhausted or the operating system terminates the process due to resource constraints.
From a technical perspective, this defect represents a classic algorithmic complexity vulnerability often categorized under CWE-835: Loop with Unreachable Exit Condition (Infinite Loop). The root cause typically involves insufficient validation of input structure before entering parsing loops, particularly when handling nested triples or complex subject-predicate-object relationships that require backtracking. In many parser implementations, recursive descent parsers are used to handle the hierarchical nature of RDF data structures. If the logic does not correctly track visited nodes or enforce a maximum recursion depth for blank node identifiers and relative URIs, it can become trapped in cycles within the input graph structure. This is particularly dangerous because TTL files can be sourced from external users, APIs, or automated feeds, meaning an attacker does not necessarily need authentication to exploit this condition if the parser processes untrusted data directly.
The operational impact of this vulnerability is primarily a denial of service against the hosting application and potentially the underlying infrastructure. Since the infinite loop consumes CPU resources continuously, it can lead to significant performance degradation for other services running on the same host. In cloud-native environments or containerized deployments, such resource exhaustion may trigger automatic scaling events or cause pod restarts if health checks fail due to unresponsiveness. For real-time systems that rely on low-latency RDF processing, this vulnerability effectively halts service availability until manual intervention is required to terminate the hung process and clear any associated memory leaks that often accompany infinite loops in garbage-collected languages like Java or Python.
This type of flaw aligns with MITRE ATT&CK technique T1496: Resource Hijacking, where an adversary uses compromised resources for their own purposes, although in this specific case, the exploitation is likely unintentional and results from malformed input rather than malicious code injection. It also relates to CWE-20: Improper Input Validation, as the parser fails to reject syntactically invalid or structurally problematic data before attempting full parsing. The lack of safeguards against deeply nested or cyclic structures in RDF graphs allows a relatively small amount of crafted text to cause disproportionate system impact, highlighting the importance of robust input sanitization and resource limits in security-critical parsers.
Mitigation strategies should focus on both immediate patching and long-term architectural improvements. Organizations running affected versions must upgrade immediately to version 4.6.9 or later where this parsing logic has been corrected with proper loop termination checks and depth limiting mechanisms. For systems that cannot be patched instantly, implementing network-level rate limiting can help mitigate the impact by restricting the volume of RDF data processed per unit time. Additionally, deploying a Web Application Firewall (WAF) rule to detect and block suspiciously large or malformed TTL payloads before they reach the application layer provides an effective defense-in-depth measure. Developers should also consider integrating static analysis tools that specifically check for infinite loop patterns in recursive parsing functions during the software development lifecycle to prevent similar issues from being introduced in future releases.