CVE-2024-4018 is a high severity improper privilege management flaw that allows privilege escalation in the BeyondTrust U-Series Appliance on Windows, scored 8.8 by NVD. Versions from 3.4 before 4.0.3 are affected. Upgrade to U-Series Appliance software 4.0.3 or later.
What's affected
The record says the issue affects the BeyondTrust U-Series Appliance from version 3.4 before 4.0.3 on Windows, 64 bit. The fixed version is therefore 4.0.3, and the vendor's release notes for that version are linked in the record. This write-up did not fetch those notes, so read them for the full list of changes.
The affected area is the local appliance API modules. The description says the improper privilege management allows privilege escalation, which means a user with limited rights on the host can gain higher ones.
The vector is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H: local access, low complexity, low privileges, changed scope. The KEV flag is false and the record reports no exploitation. A sibling CVE, CVE-2024-4017, was published the same day for the same product range.
The NVD record is dated 2024-04-19 and carries the vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H, a score of 8.8 (High). Weakness class: CWE-269.
How to check if you're exposed
Open the U-Series Appliance interface and read the software version, or check the version in your BeyondTrust administration console. Compare it with 4.0.3. Anything from 3.4 up to but not including 4.0.3 is in range.
The flaw needs local access with a low privilege account on the appliance's Windows host. List who can sign in locally to those systems, and who can run code on them. If the appliance sits in a locked down server segment with few interactive users, the practical exposure is smaller, but the version still needs to move.
If you manage many appliances, record the version of each so that the next advisory is quick to match.
What to do now
- List every U-Series Appliance and its software version.
- Upgrade each one from 3.4 up to before 4.0.3 to software 4.0.3 or later, following the vendor's upgrade notes.
- Remove local sign in rights from users who do not need them on the appliance host.
- Review local administrator group membership on those systems.
- Check the 4.0.3 release notes for other fixes and plan a regular update cadence.
Why it matters
The weakness is improper privilege management, CWE-269. A component that should check the rights of its caller does not do so strictly enough, so a low privileged user can make it act with more power than it should grant.
Local privilege escalation bugs matter because attackers often start with a modest foothold, such as a stolen standard account. Fixing them turns that foothold back into a limited one. Patch the appliance and keep the number of local users small.
Quick check
Which version fixes CVE-2024-4018?
BeyondTrust U-Series Appliance software 4.0.3. The record says versions from 3.4 before 4.0.3 are affected.
Can this be exploited remotely?
The vector is local, so an attacker needs to run code or sign in on the host first.
Sources
Last reviewed: 19 October 2026.
