CVE-2022-32149 in Google
Summary
by MITRE • 10/14/2022
An attacker may cause a denial of service by crafting an Accept-Language header which ParseAcceptLanguage will take significant time to parse.
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Analysis
by VulDB Data Team • 05/16/2025
The vulnerability identified as CVE-2022-32149 represents a significant denial of service weakness in applications that process HTTP Accept-Language headers. This flaw manifests when the ParseAcceptLanguage function encounters specially crafted headers that cause it to consume excessive processing time during parsing operations. The issue stems from the parsing algorithm's inability to efficiently handle malformed or maliciously constructed language negotiation headers, creating a potential avenue for attackers to exhaust system resources through carefully constructed requests.
This vulnerability operates at the application layer and specifically targets HTTP request processing components that handle content negotiation through language headers. The technical flaw lies in the inefficient parsing implementation where the ParseAcceptLanguage function does not employ bounded computational complexity when processing input. When an attacker crafts an Accept-Language header with nested wildcards, excessive nesting, or other malformed constructs, the parsing routine enters into computationally expensive operations that can stretch over several seconds or even minutes depending on the header complexity. The vulnerability directly maps to CWE-400, which categorizes unchecked resource consumption as a weakness that can lead to denial of service conditions.
The operational impact of this vulnerability extends beyond simple service disruption to encompass broader system reliability concerns. An attacker can exploit this weakness by sending a single malicious request containing a crafted Accept-Language header that causes the application to spend disproportionate time parsing the input. This resource exhaustion can affect not only the specific request processing but also impact the overall application performance, potentially causing cascading failures in systems that rely on rapid response times. The vulnerability affects web servers, application frameworks, and any software components that parse HTTP Accept-Language headers as part of their normal operation, making it particularly dangerous in high-traffic environments where resource exhaustion can quickly lead to complete service unavailability.
Mitigation strategies for CVE-2022-32149 should focus on implementing input validation and rate limiting measures to prevent resource exhaustion attacks. Organizations should deploy strict limits on header size and parsing complexity, ensuring that Accept-Language headers are processed with bounded computational resources. The implementation should include defensive programming practices such as maximum nesting depth limits, time budgeting for parsing operations, and early termination of suspicious parsing attempts. Additionally, employing web application firewalls with signature-based detection capabilities can help identify and block malicious header patterns before they reach the vulnerable parsing functions. From an ATT&CK framework perspective, this vulnerability aligns with the T1499.004 technique related to network denial of service, where attackers leverage application-level weaknesses to exhaust system resources. System administrators should also implement monitoring and alerting mechanisms to detect unusual parsing times or resource consumption patterns that may indicate exploitation attempts.