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…
Browse: All 2026 CVEs · All vendors
- CVSS score
- 8.8 High
- CVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- CISA KEV
- Yes — actively exploited (added 2026-09-21, remediation due 2026-09-24)
- Weakness (CWE)
- CWE-121
- Published
- 2026-06-16
- Last modified
- 2026-09-22
- NVD status
- Analyzed
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.
Affected products
- 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
- zyxel gs1900-48hpv2 firmware
Affected ranges per NVD CPE data; confirm exact versions in the vendor advisory.
Required action (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 each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. Federal remediation deadline: 2026-09-24.
How to prioritize this
This vulnerability is on the CISA KEV list, meaning it is being actively exploited — treat it as urgent regardless of the raw CVSS number. Use the live CVE lookup for the latest NVD data, and the CVSS 3.1 calculator to model your own environmental score.
References
- https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-stack-based-buffer-overflow-vulnerability-in-gs1900-series-switches-06-16-2026
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-7273
- https://www.greynoise.io/blog/open-season-on-kapibala-attacker-steals-government-records-wordpress-exploitation
FAQ
Is CVE-2026-7273 actively exploited?
Yes. CISA added CVE-2026-7273 to its Known Exploited Vulnerabilities (KEV) catalog on 2026-09-21, with a federal remediation deadline of 2026-09-24. A KEV listing means real-world exploitation is confirmed, so patching this should be prioritized above many higher-CVSS bugs that aren't being exploited.
What is the CVSS score of CVE-2026-7273?
CVE-2026-7273 has a CVSS base score of 8.8 (High). Its vector string is CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Related vulnerabilities
- CVE-2024-40891 — Zyxel DSL CPE Devices
- CVE-2024-40890 — Zyxel DSL CPE Devices
- CVE-2024-11667 — Zyxel Multiple Firewalls
- CVE-2017-6884 — Zyxel EMG2926 Routers
- CVE-2017-18368 — Zyxel P660HN-T1A Routers
- CVE-2023-27992 — Zyxel Multiple Network-Attached Storage (N
Data source: NVD & CISA KEV. Shown as-is; nothing added. Last generated from NVD data — re-check the live tool for updates.
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