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CVE-2026-7273

HighActively exploited (CISA KEV)

Description

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.

SeverityHigh
CVSS8.8
Exploit probability—
ProductZyxel GS1900 Series Switches
PublishedJun 16, 2026
First seenJun 16, 2026
Added to KEVSep 21, 2026
Weakness typeCWE-121CWE-121

How to fix

CISA required action

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 each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

CISA due date: Sep 24, 2026
Update
  • zyxel gs1900-48_firmware2.90\(aahn.2\)c0 or later
  • zyxel gs1900-8_firmware2.90\(aahh.2\)c0 or later
  • zyxel gs1900-8hp_firmware2.90\(aahi.2\)c0 or later
  • zyxel gs1900-10hp_firmware2.90\(aazi.2\)c0 or later
  • zyxel gs1900-16_firmware2.90\(aahj.2\)c0 or later
  • zyxel gs1900-24_firmware2.90\(aahl.2\)c0 or later
  • zyxel gs1900-24e_firmware2.90\(aahk.2\)c0 or later
  • zyxel gs1900-24ep_firmware2.90\(abto.2\)c0 or later
  • zyxel gs1900-24hpv2_firmware2.90\(abtp.2\)c0 or later
  • zyxel gs1900-48hpv2_firmware2.90\(abtq.2\)c0 or later
Vendor advisories

Affected products

ProductAffected versionsFixed in
zyxel gs1900-48_firmwarev < 2.90\(aahn.2\)c02.90\(aahn.2\)c0
zyxel gs1900-8_firmwarev < 2.90\(aahh.2\)c02.90\(aahh.2\)c0
zyxel gs1900-8hp_firmwarev < 2.90\(aahi.2\)c02.90\(aahi.2\)c0
zyxel gs1900-10hp_firmwarev < 2.90\(aazi.2\)c02.90\(aazi.2\)c0
zyxel gs1900-16_firmwarev < 2.90\(aahj.2\)c02.90\(aahj.2\)c0
zyxel gs1900-24_firmwarev < 2.90\(aahl.2\)c02.90\(aahl.2\)c0
zyxel gs1900-24e_firmwarev < 2.90\(aahk.2\)c02.90\(aahk.2\)c0
zyxel gs1900-24ep_firmwarev < 2.90\(abto.2\)c02.90\(abto.2\)c0
zyxel gs1900-24hpv2_firmwarev < 2.90\(abtp.2\)c02.90\(abtp.2\)c0
zyxel gs1900-48hpv2_firmwarev < 2.90\(abtq.2\)c02.90\(abtq.2\)c0

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