What’s Vulnerable › Vulnerabilities

CVE-2026-17251: Unauthenticated Denial of Service via Null Pointer Dereference in HTTP Request Parsing

• Severity: high (CVSS 7.1 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-21 · updated 2026-10-14
• Weakness: CWE-476

Description

A NULL pointer dereference vulnerability exists in the HTTP request parsing functionality of  TL-MR6400 v7. An unauthenticated remote attacker can trigger the vulnerability by sending a specially crafted HTTP request containing a malformed session cookie header. Successful exploitation may cause the HTTP service process to crash, resulting in a denial-of-service condition and temporary loss of management or CGI functionality until service recovery.

Affected products

• TP-Link Systems Inc. TL-MR6400 v7.0: before 1.9.0 Build 260714 — fixed in 1.9.0 Build 260714

How to fix

Upgrade to a fixed version: TP-Link Systems Inc. TL-MR6400 v7.0 1.9.0 Build 260714. Check the vendor advisory for mitigations.

References

• https://www.tp-link.com/en/support/download/tl-mr6400/v7/#Firmware
• https://www.tp-link.com/tw/support/download/tl-mr6400/v7/#Firmware
• https://www.tp-link.com/us/support/faq/5259/

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