CVE-2026-7273
HighExploitedPublic exploitA 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.
Published Jun 16, 2026 · Updated Sep 22, 2026 · Also known as EUVD-2026-37030, GHSA-rrv4-8jq5-8j78, TR-26-0386
Key Facts
Patch immediately- CVE-2026-7273 is a high-severity vulnerability (CVSS 8.8 v3.1) affecting GS1900-10HP firmware (Zyxel), GS1900-16 firmware (Zyxel), GS1900-24E firmware (Zyxel) and 7 more products.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Sep 21, 2026. Public exploit code is available.
- EPSS estimates a 2.5% probability of exploitation in the next 30 days.
- Fixed versions are available, including GS1900-10HP firmware 2.90\(aazi.2\)c0, GS1900-16 firmware 2.90\(aahj.2\)c0, GS1900-24 firmware 2.90\(aahl.2\)c0.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
8.8
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
2.5%
Higher than 84.4% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
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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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Sep 21, 2026 | Sep 24, 2026 | Not reported |
| Industry KEV feed | Sep 21, 2026 | Sep 24, 2026 | Not reported |
| CIRCL KEV | Sep 21, 2026 | Sep 24, 2026 | Not reported |
| ENISA EUVD | Sep 21, 2026 | n/a | Not reported |
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.
Affected Products
30 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| GS1900-10HP firmwareZyxel | >= <= 2.90(AAZI.1)C0 | 2.90\(aazi.2\)c0 |
| GS1900-16 firmwareZyxel | >= <= 2.90(AAHJ.1)C0 | 2.90\(aahj.2\)c0 |
| GS1900-24E firmwareZyxel | >= <= 2.90(AAHK.1)C0 | 2.90\(aahk.2\)c0 |
| GS1900-24EP firmwareZyxel | >= <= 2.90(ABTO.1)C0 | 2.90\(abto.2\)c0 |
| GS1900-24 firmwareZyxel | >= <= 2.90(AAHL.1)C0 | 2.90\(aahl.2\)c0 |
Patched Releases
GS1900-10HP firmware
2.90\(aazi.2\)c0
GS1900-16 firmware
2.90\(aahj.2\)c0
GS1900-24 firmware
2.90\(aahl.2\)c0
GS1900-24E firmware
2.90\(aahk.2\)c0
GS1900-24EP firmware
2.90\(abto.2\)c0
GS1900-24HPv2 firmware
2.90\(abtp.2\)c0
GS1900-48 firmware
2.90\(aahn.2\)c0
GS1900-48HPv2 firmware
2.90\(abtq.2\)c0
GS1900-8 Firmware
2.90\(aahh.2\)c0
GS1900-8HP firmware
2.90\(aahi.2\)c0
Timeline
Publicly disclosed
Jun 16, 2026
Added to CISA KEV
Sep 21, 2026
Added to Industry KEV feed
Sep 21, 2026
Added to CIRCL KEV
Sep 21, 2026
Added to ENISA EUVD
Sep 21, 2026
Last updated
Sep 22, 2026
Weakness Type
- CWE-121 Stack-based Buffer Overflow
References
- advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2026-7273
- advisoryUSOM advisory
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
- otherhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-7273
FAQ
Common Questions.
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: GS1900-10HP firmware (Zyxel) versions >= <= 2.90(AAZI.1)C0; GS1900-16 firmware (Zyxel) versions >= <= 2.90(AAHJ.1)C0; GS1900-24E firmware (Zyxel) versions >= <= 2.90(AAHK.1)C0, among others. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Sep 21, 2026.
Yes. It was added on Sep 21, 2026 with a federal remediation due date of Sep 24, 2026.
Public exploit code is available.
Fixed versions are available, including GS1900-10HP firmware 2.90\(aazi.2\)c0, GS1900-16 firmware 2.90\(aahj.2\)c0, GS1900-24 firmware 2.90\(aahl.2\)c0.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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