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CVE-2026-7273

HIGH 8.8 KNOWN EXPLOITED ALL-YEARS

Published 2026-06-16 · Last modified 2026-09-22 · Zyxel · NVD: Analyzed

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.

ACTIVELY EXPLOITED

Confirmed exploited in the wild — in CISA KEV since 2026-09-21. Patch or mitigate now.

Exploitation likelihood

2.8%chance of exploitation in 30 days · 86th percentile

● In CISA KEV (2026-09-21)○ Catalogued PoC◆ SSVC: exploitation active, automatable no

Impact if exploited

8.8CVSS 3.1 · HIGH · CNA

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ⚠Access: Must sit on the same / adjacent network
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

Search for new PoCs

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Tracked sources are checked weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Affected

Vendors Zyxel

Products Gs1900 48hpv2 Firmware Gs1900 8 Firmware Gs1900 8hp Firmware Gs1900 10hp Firmware Gs1900 16 Firmware Gs1900 24 Firmware Gs1900 24e Firmware Gs1900 24ep Firmware Gs1900 24hpv2 Firmware Gs1900 48 Firmware Gs1900 8 Gs1900 8hp Gs1900 10hp Gs1900 16 Gs1900 24 Gs1900 24e Gs1900 24ep Gs1900 24hpv2 Gs1900 48 Gs1900 48hpv2

Weakness (CWE)

  • CWE-121: Stack-based buffer overflow

CVSS vector

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References and research data (JSON)

Additional exploitation reports

Source-specific reports, separate from CISA KEV. Repeated observations from one source are not independent confirmations.

  • VulnCheck KEV · 2026-09-21T00:00:00Z

    Source guidance: 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.

    Source ransomware assessment: Unknown

    VulnCheck KEV · CVE-2026-7273 · Updated 2026-09-21T00:00:00Z
  • VulnCheck KEV · 2026-09-21T00:00:00ZVulnCheck KEV · CVE-2026-7273
    VulnCheck KEV · CVE-2026-7273

Known Affected Software Configurations

VendorProductVersion range
ZyxelGs1900 8 Firmware< 2.90\(aahh.2\)c0
ZyxelGs1900 8hp Firmware< 2.90\(aahi.2\)c0
ZyxelGs1900 10hp Firmware< 2.90\(aazi.2\)c0
ZyxelGs1900 16 Firmware< 2.90\(aahj.2\)c0
ZyxelGs1900 24 Firmware< 2.90\(aahl.2\)c0
ZyxelGs1900 24e Firmware< 2.90\(aahk.2\)c0
ZyxelGs1900 24ep Firmware< 2.90\(abto.2\)c0
ZyxelGs1900 24hpv2 Firmware< 2.90\(abtp.2\)c0
ZyxelGs1900 48 Firmware< 2.90\(aahn.2\)c0
ZyxelGs1900 48hpv2 Firmware< 2.90\(abtq.2\)c0

All CVSS metrics

  • HIGH 8.8 v3.1 · CNA Primary
    CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  • HIGH 8.8 v3.1 · NVD Secondary
    CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Exploit-tagged references (not proof of a PoC)

Advisories

Technical & other

Sources: NVD · CVE.org · All sources and attribution · EPSS