CVE-2025-53843CWE-121

CVE-2025-53843

High · published November 18, 2025

CVSS v3.1
7.5
EPSS
1%
Percentile
50.7
In the wild
Unconfirmed
What it is

⚠️ A crafty stack-based buffer overflow is lurking in FortiOS versions 7.6.0 to 7.6.3 and older! Just a few specially crafted packets could let an attacker execute unauthorized commands. 🔥 Think of it like a crowded elevator that suddenly gets overloaded. One extra person trying to squeeze in could cause the entire system to break down, allowing someone to push buttons without permission. 📦 If exploited, an attacker could wreak havoc by executing unauthorized code, potentially gaining control of the system. While it’s not the end of the world, it could still lead to significant disruptions and data exposure if left unpatched.

Put simply

Think of it like a crowded elevator that suddenly gets overloaded. One extra person trying to squeeze in could cause the entire system to break down, allowing someone to push buttons without permission. 📦 This vulnerability occurs due to improper handling of specially crafted packets, leading to a stack-based buffer overflow. This can allow attackers to execute arbitrary commands on the affected systems, posing a serious risk.

What to do

If exploited, an attacker could wreak havoc by executing unauthorized code, potentially gaining control of the system. While it’s not the end of the world, it could still lead to significant disruptions and data exposure if left unpatched. Fortinet users should promptly update to FortiOS version 7.6.4 or later to mitigate this vulnerability. Regularly audit your configurations and ensure that all unnecessary services are disabled to minimize attack surfaces. You've got this! With a quick patch, you'll be back to hero status in no time. 🛡️

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00655 · 50.7th percentile
Weakness
CWE-121 · Stack-based Buffer Overflow
Published
2025-11-18T22:16Z
Affected products (2)
ProductVersionsFixed in
fortinet/fortios≥ 6.4.0, < 7.4.97.4.9
fortinet/fortios≥ 7.6.0, < 7.6.47.6.4
References (2)
EPSS history
Timeline
  • 18 NOV 17:01Z
    A stack-based buffer overflow vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2 all versions, FortiOS 7.0 all…
    cvelistv5