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Gs1900 48hpv2 FirmwareOperating system · Zyxel

CVE-2023-35140

MEDIUM · 5.5 CVSS v3.1 Published 2023-11-07
Fix available
A fix is available. Upgrade to after 2.70 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click

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 · unedited
The improper privilege management vulnerability in the Zyxel GS1900-24EP switch firmware version V2.70(ABTO.5) could allow an authenticated local user with read-only access to modify system settings on a vulnerable device.

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 confidence

This is a privilege management vulnerability in Zyxel GS1900-24EP switches running firmware V2.70(ABTO.5). The device fails to properly enforce read-only access controls, allowing authenticated users with limited (read-only) privileges to modify system settings they should not be able to change. This represents a privilege escalation issue where the authorization mechanism does not correctly restrict users based on their assigned role.

MitigationApply the vendor-supplied firmware patch from Zyxel to address the improper privilege management. Until patched, limit administrative access to trusted personnel and monitor for unauthorized configuration changes.

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
Gs1900 48hpv2 FirmwareOperating system
Affected:<= 2.70\(abtq.5\)
Gs1900 48 FirmwareOperating system
Affected:<= 2.70\(aahn.5\)
Gs1900 24hpv2 FirmwareOperating system
Affected:<= 2.70\(abtp.5\)
Gs1900 24ep FirmwareOperating system
Affected:<= 2.70\(abto.5\)
Gs1900 24e FirmwareOperating system
Affected:<= 2.70\(aahk.5\)
Gs1900 24 FirmwareOperating system
Affected:<= 2.70\(aahl.5\)
Gs1900 16 FirmwareOperating system
Affected:<= 2.70\(aahj.5\)
Gs1900 10hp FirmwareOperating system
Affected:<= 2.70\(aazi.5\)

CVSS 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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the GS1900 switch model
    Access the web UI (typically http://<device-ip>) and check the System Info page, or use CLI command 'show system-info' or SNMP query snmpwalk on OID 1.3.6.1.2.1.1.1
    Affected if Model is GS1900-48hpv2, GS1900-48, GS1900-24hpv2, GS1900-24ep, GS1900-24e, GS1900-24, GS1900-16, or GS1900-10hp
  2. Check the installed firmware version
    In the web UI go to Maintenance > Firmware Upgrade or use CLI command 'show version' to view the firmware build number
    Affected if Firmware version is 2.70 with build number ABTO.5, ABTQ.5, ABTP.5, AAHN.5, AAHK.5, AAHJ.5, AAZI.5, or AALL.5, or any version lower than these in the 2.70 branch
  3. Verify read-only user accounts exist
    In the web UI go to AAA > User Account or use CLI command 'show user' to list all configured accounts and their privilege levels
    Affected if Any user account is configured with read-only (or 'user') privilege level in addition to admin accounts
  4. Confirm admin access to verify role enforcement
    Log in with a read-only user account and attempt to modify a system setting (such as changing a port configuration or viewing admin-only areas). Check if the web UI or CLI allows changes that should be restricted to admin roles
    Affected if Read-only users can successfully modify settings or access administrative functions that should be restricted to admin-level accounts

Your environment is affected if you run any of the listed GS1900 models with firmware version 2.70 or lower AND have read-only user accounts configured, as these users could escalate privileges to modify restricted settings.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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.

From vendor data
Upgrade available Upgrade to a release after 2.70
Interim mitigation

Apply the vendor-supplied firmware patch from Zyxel to address the improper privilege management. Until patched, limit administrative access to trusted personnel and monitor for unauthorized configuration changes.

Fix this in Gs1900 48hpv2 Firmware Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,664.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-35140 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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