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Fencer Vulns
high 8.8

CVE-2026-7273 kev in the critical feed json

A stack-based buffer overflow vulnerability in the CGI program of Zyxel GS1900-48HPv2 firmware versions through 2.90(ABTQ.1)C0 could allow…

published 2026-06-16 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-37030

cvss
8.8
version 3.1, CNA
cisa kev
Exploited
added 2026-09-21
epss
2.7%
EPSS 2.7% chance of exploitation in 30 days, percentile 86%
public exploits
0
none known

Summary

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.

Patch / 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.

  • zyxel gs1900-8_firmware 2.90\(aahh.2\)c0
  • zyxel gs1900-8hp_firmware 2.90\(aahi.2\)c0
  • zyxel gs1900-10hp_firmware 2.90\(aazi.2\)c0
  • zyxel gs1900-16_firmware 2.90\(aahj.2\)c0
  • zyxel gs1900-24_firmware 2.90\(aahl.2\)c0
  • zyxel gs1900-24e_firmware 2.90\(aahk.2\)c0
  • zyxel gs1900-24ep_firmware 2.90\(abto.2\)c0
  • zyxel gs1900-24hpv2_firmware 2.90\(abtp.2\)c0
  • zyxel gs1900-48_firmware 2.90\(aahn.2\)c0
  • zyxel gs1900-48hpv2_firmware 2.90\(abtq.2\)c0

Timeline

  1. Published
  2. CISA SSVC: exploitation active
  3. Added to CISA KEV
  4. CISA patch deadline

Known exploited

Added
49 d ago
Patch by
2026-09-24 (46 d ago)
Ransomware
Not known
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.
Vendor, product
Zyxel, GS1900 Series Switches
CISA name
Zyxel GS1900 Series Switches Stack-Based Buffer Overflow Vulnerability

CISA SSVC

Exploitation
Active, exploited in the wild
Automatable
no
Technical impact
total
Assessed
4 mo ago

Exploit prediction

2.73% chance of exploitation in the next 30 days, higher than 86% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • greynoise.io https://www.greynoise.io/blog/open-season-on-kapibala-attacker-steals-government-records-wordpress-exploitation referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Zyxel GS1900-48HPv2 firmware
  • Zyxel GS1900-8 firmware
  • Zyxel GS1900-8HP firmware
  • Zyxel GS1900-10HP firmware
  • Zyxel GS1900-16 firmware
  • Zyxel GS1900-24 firmware
  • Zyxel GS1900-24E firmware
  • Zyxel GS1900-24EP firmware
  • Zyxel GS1900-24HPv2 firmware
  • Zyxel GS1900-48 firmware

Classification

Weakness
  • CWE-121 Stack-based Buffer Overflow

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.