CVE-2026-22904
Improper length handling when parsing multiple cookie fields (including TRACKID) allows an unauthenticated remote attacker to send oversized cookie values and trigger a stack buffer overflow, resultin...
Overview
A critical vulnerability exists in how certain web servers or applications handle HTTP cookies. The flaw occurs when parsing multiple cookie fields, including a field often named TRACKID. Due to improper checks on the length of cookie values, an attacker can send an excessively large cookie, causing a stack buffer overflow.
Vulnerability Explained
Think of a cookie as a small note a website gives your browser to remember information. The vulnerable software has a specific-sized “slot” (a buffer on the stack) to hold the value of these cookie notes. Normally, it checks the note’s length to ensure it fits. This vulnerability means that check is missing or flawed for certain cookie types.
An attacker can craft a malicious HTTP request containing an extremely long cookie value. When the software tries to process this oversized data, it overflows the designated slot, corrupting adjacent memory. This corruption is the core of the vulnerability.
Potential Impact
The impact of this flaw is severe, earning a CVSS score of 9.8 (CRITICAL).
- Denial-of-Service (DoS): The most immediate result is likely a crash of the affected service, making it unavailable to legitimate users.
- Remote Code Execution (RCE): By carefully crafting the oversized data, an attacker could potentially take control of the underlying system. This would allow them to install malware, steal data, or use the server as a foothold for further attacks.
- Attack Simplicity: The vulnerability can be exploited by an unauthenticated attacker from a remote network, making it highly accessible to threat actors.
Remediation and Mitigation
Immediate action is required to protect affected systems.
Primary Action: Patching
- Identify Affected Software: Determine if you are using the vulnerable software component (e.g., a specific web server, application server, or embedded device firmware). Consult your vendor’s security advisory.
- Apply Updates: Apply the official security patch provided by the software vendor as soon as it is available. This is the only complete solution.
Immediate Mitigations (If a Patch is Not Yet Available):
- Network Controls: Use a Web Application Firewall (WAF) to block HTTP requests containing abnormally long cookie values. Create rules to inspect and limit cookie header sizes.
- Segmentation: Restrict network access to the vulnerable service using firewalls, allowing connections only from trusted sources (e.g., a load balancer or specific IP ranges).
- Monitor for Exploits: Increase monitoring for crashes or unusual activity on the affected service. Review logs for patterns of very large HTTP headers.
General Advice: Treat this as a high-priority issue. Test patches in a development environment before widespread deployment, but do not delay patching production systems due to the high risk of exploitation.