CVE-2026-7273A 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 an…
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It affects Zyxel GS1900-48HPv2 firmware and 19 other products. Add what you run to find out whether that includes you.
CISA lists it as known exploited since Sep 21, 2026; federal agencies had to remediate by Sep 24, 2026. Treat that date as your deadline.
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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.
- CVSS
- 8.8 HIGH (v3.1, CNA)CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-121
- Known exploited
- Added to CISA KEV Sep 21, 2026; federal remediation due Sep 24, 2026Apply 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.
- EPSS (exploitation in the next 30 days)
- 2.50% (percentile 84)
- Assigned by
- Zyxel
- NVD analysis
- Analyzed
- Record last updated
- Sep 22, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Zyxel GS1900-48HPv2 firmware zyxel:gs1900_48hpv2_firmware (from the name) | through 2.90(ABTQ.1)C0 | CNA record |
Zyxel GS1900-8 firmware zyxel:gs1900_8_firmware (from the name) | through 2.90(AAHH.1)C0 | CNA record |
Zyxel GS1900-8HP firmware zyxel:gs1900_8hp_firmware (from the name) | through 2.90(AAHI.1)C0 | CNA record |
Zyxel GS1900-10HP firmware zyxel:gs1900_10hp_firmware (from the name) | through 2.90(AAZI.1)C0 | CNA record |
Zyxel GS1900-16 firmware zyxel:gs1900_16_firmware (from the name) | through 2.90(AAHJ.1)C0 | CNA record |
Zyxel GS1900-24 firmware zyxel:gs1900_24_firmware (from the name) | through 2.90(AAHL.1)C0 | CNA record |
Zyxel GS1900-24E firmware zyxel:gs1900_24e_firmware (from the name) | through 2.90(AAHK.1)C0 | CNA record |
Zyxel GS1900-24EP firmware zyxel:gs1900_24ep_firmware (from the name) | through 2.90(ABTO.1)C0 | CNA record |
Zyxel GS1900-24HPv2 firmware zyxel:gs1900_24hpv2_firmware (from the name) | through 2.90(ABTP.1)C0 | CNA record |
Zyxel GS1900-48 firmware zyxel:gs1900_48_firmware (from the name) | through 2.90(AAHN.1)C0 | CNA record |
zyxel gs1900-8_firmware zyxel:gs1900-8_firmware | before 2.90\(aahh.2\)c0 | NVD |
zyxel gs1900-8hp_firmware zyxel:gs1900-8hp_firmware | before 2.90\(aahi.2\)c0 | NVD |
zyxel gs1900-10hp_firmware zyxel:gs1900-10hp_firmware | before 2.90\(aazi.2\)c0 | NVD |
zyxel gs1900-16_firmware zyxel:gs1900-16_firmware | before 2.90\(aahj.2\)c0 | NVD |
zyxel gs1900-24_firmware zyxel:gs1900-24_firmware | before 2.90\(aahl.2\)c0 | NVD |
zyxel gs1900-24e_firmware zyxel:gs1900-24e_firmware | before 2.90\(aahk.2\)c0 | NVD |
zyxel gs1900-24ep_firmware zyxel:gs1900-24ep_firmware | before 2.90\(abto.2\)c0 | NVD |
zyxel gs1900-24hpv2_firmware zyxel:gs1900-24hpv2_firmware | before 2.90\(abtp.2\)c0 | NVD |
zyxel gs1900-48_firmware zyxel:gs1900-48_firmware | before 2.90\(aahn.2\)c0 | NVD |
zyxel gs1900-48hpv2_firmware zyxel:gs1900-48hpv2_firmware | before 2.90\(abtq.2\)c0 | NVD |
References
- https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-stack-based-buffer-overflow-vulnerability-in-gs1900-series-switches-06-16-2026vendor-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-7273third-party-advisory, us-government-resource
- https://www.greynoise.io/blog/open-season-on-kapibala-attacker-steals-government-records-wordpress-exploitationexploit, third-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.