CVE-2025-63658

A stack overflow in the mk_http_index_lookup function (mk_server/mk_http.c) of monkey commit f37e984 allows attackers to cause a Denial of Service (DoS) via…

High · published January 29, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
70.0
In the wild
Unconfirmed
What it is

⚡ A single crafted HTTP request can trigger a stack overflow in the mk_http_index_lookup function, sending your server into a tailspin! 😱 Think of your server like a busy restaurant kitchen. If a chef receives an order they can’t handle—like an impossibly large pizza to make all at once—the whole kitchen can get overwhelmed and shut down, leaving hungry customers in the lurch. This vulnerability could cause your server to crash, denying access to legitimate users and potentially disrupting services. If an attacker sends a malicious request, they could render your website unusable until the server is restarted, leading to lost revenues and frustrated users.

Put simply

Think of your server like a busy restaurant kitchen. If a chef receives an order they can’t handle—like an impossibly large pizza to make all at once—the whole kitchen can get overwhelmed and shut down, leaving hungry customers in the lurch. The stack overflow occurs in the mk_http_index_lookup function, allowing attackers to exploit the server by sending specially crafted HTTP requests, which can overwhelm the stack and lead to a Denial of Service (DoS).

What to do

This vulnerability could cause your server to crash, denying access to legitimate users and potentially disrupting services. If an attacker sends a malicious request, they could render your website unusable until the server is restarted, leading to lost revenues and frustrated users. To protect against this vulnerability, update to the patched version of Monkey as soon as it's available. Additionally, you can implement input validation on HTTP requests to mitigate the risk of such crafted requests in the meantime. 🛡️ You've got this! By taking these steps, you can safeguard your server and keep everything running smoothly! 🚀

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.01290 · 70.0th percentile
Published
2026-01-29T00:00Z
EPSS history
Timeline
  • 29 JAN 00:00Z
    A stack overflow in the mk_http_index_lookup function (mk_server/mk_http.c) of monkey commit f37e984 allows attackers to cause a Denial of Service (DoS) via…
    cvelistv5