Improper error message handling in Zyxel ZyWALL/USG series firmware versions 4.60 through 4.73, VPN series firmware versions 4.60 through 5.
Affects Zyxel ZyWALL/USG firmware ZLD V4.60 to V4.73 and VPN, USG FLEX and ATP firmware ZLD V4.60 to V5.35. Fixed in V4.73 Patch 1 for ZyWALL/USG and in V5.36 for the other series.
- 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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
- 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
Zyxel ZyWALL, USG, VPN, USG FLEX, and ATP series firmware are affected. An unauthenticated remote attacker could send specially crafted packets to an affected device to run some operating system commands on it.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original description
Improper error message handling in Zyxel ZyWALL/USG series firmware versions 4.60 through 4.73, VPN series firmware versions 4.60 through 5.35, USG FLEX series firmware versions 4.60 through 5.35, and ATP series firmware versions 4.60 through 5.35, which could allow an unauthenticated attacker to execute some OS commands remotely by sending crafted packets to an affected device.
Timeline
- CVE published
- Added to CISA KEV
CISA has evidence of exploitation in the wild
- CISA remediation deadline
Due date for US federal agencies to patch
- Record last updated
- EPSS reached 10%
FIRST estimates at least a 10% chance of exploitation in the next 30 days
Affected versions
- Zyxel ZyWALL/USG series firmware
4.60 through 4.73
- Zyxel VPN series firmware
4.60 through 5.35
- Zyxel USG FLEX series firmware
4.60 through 5.35
- Zyxel ATP series firmware
4.60 through 5.35
References 2
Questions about CVE-2023-28771
What does this mean?
Improper error message handling could allow an unauthenticated attacker to execute some OS commands remotely on the affected device.Source: zyxel.com
Am I affected, and how do I check?
Affected are ZyWALL/USG firmware ZLD V4.60 to V4.73 and VPN, USG FLEX and ATP firmware ZLD V4.60 to V5.35. Compare the firmware version reported by the device against these ranges.Source: zyxel.com
What should I do about it?
Upgrade ZyWALL/USG firmware to V4.73 Patch 1, or VPN, USG FLEX and ATP firmware to V5.36.Source: zyxel.com
Is it being exploited?
Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2023-05-31, which means it has evidence of attacks. No public exploit code is tracked.Source: cisa.gov, cve.now feed data
What if there's no patch?
The checked facts list no workaround. Until fixed firmware is installed, no mitigation is listed for affected devices.Source: zyxel.com