Known exploited vulnerability
CVE-2023-28771
The short answer
CVE-2023-28771 affects Zyxel ZyWALL/USG series firmware and is rated critical (CVSS 9.8). CISA added it to the Known Exploited Vulnerabilities catalog on 2023-05-31: attackers are using it, so patch it first.
What it is
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.
Weakness: CWE-78.
Severity
9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploited (CISA KEV)
Yes, since May 31, 2023
Federal due date Jun 21, 2023
EPSS, next 30 days
99%
Higher than 100% of scored CVEs
How it can be exploited
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
What CISA says to do
Apply updates per vendor instructions.
Affected products
ZyWALL/USG series firmware, VPN series firmware, USG FLEX series firmware, ATP series firmware. NVD's record lists the exact affected versions.
References
- www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-remote-command-injection-vulnerability-of-firewalls Vendor Advisory
- www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-remote-command-injection-vulnerability-of-firewalls Vendor Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-28771 US Government Resource
Questions
Is CVE-2023-28771 being exploited?
Yes. CISA added CVE-2023-28771 to its Known Exploited Vulnerabilities catalog on 2023-05-31, with a federal remediation due date of 2023-06-21.
How do I fix CVE-2023-28771?
CISA's required action: Apply updates per vendor instructions.
From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.
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