CVE-2025-63649

An out-of-bounds read in the http_parser_transfer_encoding_chunked function (mk_server/mk_http_parser.c) of monkey commit f37e984 allows attackers to cause a…

High · published January 29, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
64.0
In the wild
Unconfirmed
What it is

⚡ A crafty crafted POST request can trigger a Denial of Service by exploiting an out-of-bounds read in Monkey's HTTP parser! 🔥 Think of this like a waiter at a restaurant serving a dish that’s missing key ingredients because the order slipped through the cracks—when the server can't handle the request correctly, it creates chaos in the kitchen! If an attacker sends this specially crafted request, it could cause the server to crash or become unresponsive, leaving users without access. This is particularly concerning for any service relying on Monkey, as downtime can lead to lost revenue and frustrated users.

Put simply

Think of this like a waiter at a restaurant serving a dish that’s missing key ingredients because the order slipped through the cracks—when the server can't handle the request correctly, it creates chaos in the kitchen! This vulnerability in the http_parser_transfer_encoding_chunked function allows attackers to exploit an out-of-bounds read, causing the server to enter an unstable state when processing improperly formatted requests.

What to do

If an attacker sends this specially crafted request, it could cause the server to crash or become unresponsive, leaving users without access. This is particularly concerning for any service relying on Monkey, as downtime can lead to lost revenue and frustrated users. To safeguard against this, immediately patch to the latest version of Monkey that addresses CVE-2025-63649. Additionally, monitor your server logs for unusual POST request patterns that might indicate an attempt to exploit this issue. You've got this! With a quick patch, you can keep your server up and 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
0.01050 · 64.0th percentile
Published
2026-01-29T00:00Z
EPSS history
Timeline
  • 29 JAN 00:00Z
    An out-of-bounds read in the http_parser_transfer_encoding_chunked function (mk_server/mk_http_parser.c) of monkey commit f37e984 allows attackers to cause a…
    cvelistv5