CVE-2024-42057
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA command injection vulnerability in the IPSec VPN feature of Zyxel ATP series firmware versions from V4.32 through V5.38, USG FLEX series firmware versions from V4.50 through V5.38, USG FLEX 50(W) series firmware versions from V4.16 through V5.38, and USG20(W)-VPN series firmware versions from V4.16 through V5.38 could allow an unauthenticated attacker to execute some OS commands on an affected device by sending a crafted username to the vulnerable device. Note that this attack could be successful only if the device was configured in User-Based-PSK authentication mode and a valid user with a long username exceeding 28 characters exists.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA command injection vulnerability in the IPSec VPN feature of Zyxel ATP, USG FLEX, USG FLEX 50(W), and USG20(W)-VPN series allows unauthenticated attackers to execute OS commands by sending a crafted username. Successful exploitation requires the device to have User-Based-PSK authentication enabled and a valid user account with a username exceeding 28 characters.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 4.32, < 5.39>= 4.50, < 5.39>= 4.16, < 5.39CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check firmware versionAccess the device CLI or web interface and retrieve the firmware version. In CLI, use 'show system-info' or 'firmware version' command. In web UI, check under Maintenance > Firmware or System Status.Affected if Firmware version is >= 4.32 and < 5.39, OR >= 4.50 and < 5.39, OR >= 4.16 and < 5.39 (all Zld firmware branches within these ranges are affected)
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Verify IPSec VPN is configuredCheck if IPSec VPN is active on the device through the web interface under VPN > IPSec or via CLI commands such as 'show ipsec sa' or 'show ipsec config'.Affected if IPSec VPN is configured and active on the device
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Confirm User-Based-PSK authentication is enabledNavigate to the IPSec VPN settings in the web interface (VPN > IPSec > User-Based-PSK) or use CLI to check the authentication mode configuration.Affected if User-Based-PSK authentication mode is enabled for IPSec VPN
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Identify user accounts with usernames exceeding 28 charactersReview all user accounts configured for IPSec VPN authentication under VPN > IPSec > User or AAA > User Management. Count the characters in each username field.Affected if Any valid user account exists with a username containing more than 28 characters
Device is affected if it runs an affected Zld firmware version, has User-Based-PSK authentication enabled, and contains at least one user account with a username longer than 28 characters.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped5.39
Upgrade firmware to a version beyond V5.38. If immediate upgrade is not feasible, remove or shorten any user accounts with usernames exceeding 28 characters and consider disabling User-Based-PSK authentication mode until the patch can be applied.
Firmware version 5.39 or later for affected Zyxel ATP, USG FLEX, USG FLEX 50(W), and USG20(W)-VPN series devices
- 1. Identify the exact model of your Zyxel device (ATP series, USG FLEX series, USG FLEX 50(W) series, or USG20(W)-VPN series)
- 2. Navigate to Zyxel support website (www.zyxel.com) and locate the firmware download section for your specific model
- 3. Download firmware version 5.39 or later for your device model
- 4. Review the firmware release notes to confirm the security fix for CVE-2024-42057 is included
- 5. Backup the current device configuration before upgrading
- 6. Upload and apply the new firmware via the device's web interface or CLI
- 7. After reboot, verify the device is functioning normally and the firmware version shows the upgrade
- 8. If User-Based-PSK authentication is not required, consider disabling it as an additional hardening measure
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2024-42057 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2024-42057 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data