SB2026110574 - Remote code execution in Zyxel GS1900 series switches
Published: November 5, 2026
Security Bulletin ID
SB2026110574
CSH Severity
Critical
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Code execution
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Out-of-bounds write (CVE-ID: CVE-2026-107441) Exploited
CWE-ID: CWE-787 - Out-of-bounds write
CVSSv4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to compromise vulnerable system.
The vulnerability exists due to a boundary error in the CGI program. A remote non-authenticated attacker can send specially crafted HTTP POST requests to the affected device, trigger an out-of-bounds write and execute arbitrary code on the target system.
Note, the vulnerability is being actively exploited in the wild.
Remediation
Install update from vendor's website.
References
- https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-out-of-bounds-write-vulnerability-in-gs1900-series-switches-11-03-2026
- https://www.binarly.io/blog/zyxel-gs1900-rce-cve-2026-107441
- https://community.zyxel.com/en/discussion/34420/switch-gs1900-series-v2-90-patch-3-firmware-release