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
Affects Zyxel GS1900-48HPv2 firmware 2.90(ABTQ.1)C0 and earlier, plus several other GS1900 switch firmware builds. No vendor rating is given. Fixed in 2.90(ABTQ.2)C0 for GS1900-48HPv2.
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Listed in CISA KEV
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Actively exploited
- Fix
- Fixed in 2.90(ABTQ.2)C0
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
This vulnerability affects the web-based CGI program in the firmware of the Zyxel GS1900-48HPv2 network switch. An attacker on the local network without logging in could potentially run operating system commands on the device by sending a specially crafted web request.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original 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.
Timeline
- CVE published
- Added to CISA KEV
CISA has evidence of exploitation in the wild
- Record last updated
- CISA remediation deadline
Due date for US federal agencies to patch
Affected versions
- Zyxel GS1900-48HPv2 firmware
through 2.90(ABTQ.1)C0
- Zyxel GS1900-8 firmware
through 2.90(AAHH.1)C0
- Zyxel GS1900-8HP firmware
through 2.90(AAHI.1)C0
- Zyxel GS1900-10HP firmware
through 2.90(AAZI.1)C0
- Zyxel GS1900-16 firmware
through 2.90(AAHJ.1)C0
- Zyxel GS1900-24 firmware
through 2.90(AAHL.1)C0
- Zyxel GS1900-24E firmware
through 2.90(AAHK.1)C0
- Zyxel GS1900-24EP firmware
through 2.90(ABTO.1)C0
- Zyxel GS1900-24HPv2 firmware
through 2.90(ABTP.1)C0
- Zyxel GS1900-48 firmware
through 2.90(AAHN.1)C0
References 1
Questions about CVE-2026-7273
What does this mean?
A stack-based buffer overflow in the CGI program of the switch's web interface. The advisory says a crafted HTTP request could potentially lead to execution of OS commands.Source: zyxel.com
Am I affected, and how do I check?
Zyxel GS1900-48HPv2 firmware up to and including 2.90(ABTQ.1)C0 is listed. Other GS1900 firmware builds are also listed, each with its own last affected version: GS1900-8 through 2.90(AAHH.1)C0, GS1900-8HP through 2.90(AAHI.1)C0, GS1900-10HP through 2.90(AAZI.1)C0, GS1900-16 through 2.90(AAHJ.1)C0, GS1900-24 through 2.90(AAHL.1)C0, GS1900-24E through 2.90(AAHK.1)C0, GS1900-24EP through 2.90(ABTO.1)C0, GS1900-24HPv2 through 2.90(ABTP.1)C0, and GS1900-48 through 2.90(AAHN.1)C0. To check, compare the firmware version shown in the switch's management interface with these values.Source: zyxel.com
What should I do about it?
Upgrade GS1900-48HPv2 firmware to 2.90(ABTQ.2)C0, which is the listed fixed version.Source: zyxel.com
Is it being exploited?
Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-09-21, which means it has evidence of attacks. No public exploit code is tracked.Source: cisa.gov, cve.now feed data