CVE-2026-7273: Zyxel GS1900 Series Switches (High, CVSS 8.8)
- CVSS
- 8.8 High (v3.1)
- EPSS
- 2.8% chance of exploitation in the next 30 days (higher than 86.4% of CVEs)
- Exploited in the wild
- Yes, on CISA’s KEV list since Sep 21, 2026
- Public exploit
- None reported in public exploit databases
- Weakness
- CWE-121
- Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- Published
- Jun 16, 2026
- CISA fix-by date
- Sep 24, 2026 (for US federal agencies)
What it is
A stack-based buffer overflow vulnerability in the CGI program of Zyxel GS1900-48HPv2 firmware versions through 2.90(ABTQ.1)C0 could allow a LAN-based, unauthenticated attacker to exploit the flaw and potentially execute OS commands via a crafted HTTP request.
Description from the National Vulnerability Database.
What to do
CISA: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating
Check whether you run Zyxel GS1900 Series Switches, then apply the vendor’s fix or mitigation from the advisories below. Because this flaw is exploited or has public exploit code, treat it as urgent and check for signs of compromise, not just the patch level.
Advisories and fixes
ThreatRoundup coverage
Zyxel’s June Patch Didn’t Stop the Switch Hack. This One Does
Sources: NVD, FIRST EPSS, CISA KEV, and public exploit databases (availability only). ThreatRoundup reports whether public exploit code exists but never links to it: fake proof-of-concepts that infect security researchers are common. This page updates automatically.