CVE-2026-1459: A post-authentication command injection vulnerability in the TR-369 certificate download CGI program of the Zy
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HIGH 7.2MITIGATEMITIGATEMITIGATE
CVE-2026-1459 is a high-severity flaw (CVSS 7.2) affecting vmg3625-t50c firmware, vmg3625-t50b firmware, emg5523-t50b firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
A post-authentication command injection vulnerability in the TR-369 certificate download CGI program of the Zyxel VMG3625-T50B firmware versions through 5.50(ABPM.9.7)C0 could allow an authenticated attacker with administrator privileges to execute operating system (OS) commands on an affected device.
Why this priority
High severity
No fix is published yet: follow the downgrade or mitigation steps.
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
Published CVE record published
Updated Record last modified
zyxel vmg3625-t50c firmware MITIGATE
Affected: <= 5.50\(abpm.9.7\)c0
Fixed in: no fixed release known
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
zyxel vmg3625-t50b firmware MITIGATE
Affected: <= 5.50\(abpm.9.7\)c0
Fixed in: no fixed release known
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
zyxel emg5523-t50b firmware MITIGATE
Affected: <= 5.50\(abpm.9.7\)c0
Fixed in: no fixed release known
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
zyxel emg3525-t50b firmware MITIGATE
Affected: <= 5.50\(abpm.9.7\)c0
Fixed in: no fixed release known
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
zyxel dx5401-b1 firmware MITIGATE
Affected: <= 5.17\(abyo.7.1\)c0
Fixed in: no fixed release known
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
zyxel vmg8623-t50b firmware MITIGATE
Affected: <= 5.50\(abpm.9.7\)c0
Fixed in: no fixed release known
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
Verify at the official sourceNVD · CVE Program · Report a problem with this page Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-1459?
vmg3625-t50c firmware: mitigate or apply the listed mitigation; vmg3625-t50b firmware: mitigate or apply the listed mitigation; emg5523-t50b firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2026-1459 being exploited?
CVE-2026-1459 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-1459 affect?
CVE-2026-1459 affects vmg3625-t50c firmware, vmg3625-t50b firmware, emg5523-t50b firmware. Severity is high (CVSS 7.2). A post-authentication command injection vulnerability in the TR-369 certificate download CGI program of the Zyxel VMG3625-T50B firmware versions through 5.50(ABPM.9.7)C0 could allow an authenticated attacker with administrator privileges to
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