CVE-2025-63655

A NULL pointer dereference in the mk_http_range_parse function (mk_server/mk_http.c) of monkey commit f37e984 allows attackers to cause a Denial of Service…

High · published January 29, 2026

CVSS v3.1
7.5
EPSS
9%
Percentile
95.1
In the wild
Unconfirmed
What it is

⚡ A single crafted HTTP request is all it takes to trigger a devastating Denial of Service! This NULL pointer dereference in Monkey's mk_http_range_parse function can put your server out of commission. 🔥 Think of it as a restaurant where a customer places an absurd order that the kitchen can't understand — it just causes chaos and stops everything else from flowing smoothly. Instead of serving the actual meals, the kitchen is completely halted, leading to a backlog of hungry customers! If exploited, an attacker can essentially bring your server to its knees, causing it to become unresponsive for legitimate users. This means your web services could be unavailable, potentially leading to loss of revenue and user trust. In a world where uptime is everything, this flaw could spell disaster!

Put simply

Think of it as a restaurant where a customer places an absurd order that the kitchen can't understand — it just causes chaos and stops everything else from flowing smoothly. Instead of serving the actual meals, the kitchen is completely halted, leading to a backlog of hungry customers! The vulnerability arises from a NULL pointer dereference in the mk_http_range_parse function, allowing attackers to craft requests that the server cannot handle, leading to a Denial of Service condition.

What to do

If exploited, an attacker can essentially bring your server to its knees, causing it to become unresponsive for legitimate users. This means your web services could be unavailable, potentially leading to loss of revenue and user trust. In a world where uptime is everything, this flaw could spell disaster! To mitigate this risk, immediately update your Monkey server to the patched version. Review your HTTP request handling to ensure robust validation and error handling to prevent similar issues in the future. Regularly monitor your server logs for unusual requests. You've got this! Patch up, and your server will be safer in no time. 🛡️

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
0.08563 · 95.1th percentile
Published
2026-01-29T00:00Z
EPSS history
Timeline
  • 29 JAN 00:00Z
    A NULL pointer dereference in the mk_http_range_parse function (mk_server/mk_http.c) of monkey commit f37e984 allows attackers to cause a Denial of Service…
    cvelistv5