How severe is CVE-2026-7273?

CVE-2026-7273 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-7273 being actively exploited?

Yes. CVE-2026-7273 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-09-21, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2026-7273?

CVE-2026-7273 primarily affects Zyxel Gs1900-8 Firmware. In total, 10 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-7273?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2026-7273 have an EU (EUVD) identifier?

Yes. CVE-2026-7273 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-37030.

When was CVE-2026-7273 published?

CVE-2026-7273 was published on 2026-06-16 and last updated on 2026-09-22.

CVE-2026-7273

CVE-2026-7273 is a high-severity vulnerability in Zyxel Gs1900-8 Firmware with a CVSS 3.x base score of 8.8. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2026-09-21). The underlying weakness is classified as CWE-121.

Key facts

Severity: High (CVSS 3.x base score 8.8)
EPSS exploit prediction: 3% (84th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2026-09-21)
EU (EUVD) id: EUVD-2026-37030
Weakness: CWE-121
Affected product: Zyxel Gs1900-8 Firmware
Published: 2026-06-16
Last modified: 2026-09-22

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.

Frequently asked questions

What is CVE-2026-7273?: 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.
How severe is CVE-2026-7273?: CVE-2026-7273 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-7273 being actively exploited?: Yes. CVE-2026-7273 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-09-21, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2026-7273?: CVE-2026-7273 primarily affects Zyxel Gs1900-8 Firmware. In total, 10 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-7273?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2026-7273 have an EU (EUVD) identifier?: Yes. CVE-2026-7273 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-37030.
When was CVE-2026-7273 published?: CVE-2026-7273 was published on 2026-06-16 and last updated on 2026-09-22.

References

Affected products (10)

cpe:2.3:o:zyxel:gs1900-8_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:gs1900-8hp_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:gs1900-10hp_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:gs1900-16_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:gs1900-24_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:gs1900-24e_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:gs1900-24ep_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:gs1900-24hpv2_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:gs1900-48_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:gs1900-48hpv2_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Zyxel Gs1900-8 Firmware

CVE-2019-15800 — Critical (CVSS 9.8): An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. Due to lack of input validation in…
CVE-2019-15803 — Critical (CVSS 9.1): An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. Through an undocumented sequence…
CVE-2019-15799 — High (CVSS 8.8): An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. User accounts created through the…
CVE-2019-15804 — High (CVSS 7.5): An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. By sending a signal to the CLI…
CVE-2019-15801 — High (CVSS 7.5): An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. The firmware image contains…
CVE-2024-8881 — Medium (CVSS 6.8): A post-authentication command injection vulnerability in the CGI program in the Zyxel GS1900-48 switch firmware version…

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