Backup ServerApplication · Proxmox

CVE-2023-43320

HIGH · 8.8 CVSS v3.1 Published 2023-09-27
Fix available
A fix is available. Upgrade to after 8.0 or later.
See remediation →
94/100
Remediation priority · Urgent
Public exploit Remotely reachable Zero-click Patch available

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
An issue in Proxmox Server Solutions GmbH Proxmox VE v.5.4 thru v.8.0, Proxmox Backup Server v.1.1 thru v.3.0, and Proxmox Mail Gateway v.7.1 thru v.8.0 allows a remote authenticated attacker to escalate privileges via bypassing the two-factor authentication component.

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

A detailed technical summary for this CVE is being prepared.

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
Backup ServerApplication
Affected:>= 1.1, <= 3.0
Proxmox Mail GatewayApplication
Affected:>= 7.1, <= 8.0
Virtual EnvironmentApplication
Affected:>= 5.4, <= 8.0

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

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

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 · scoped
Upgrade available Upgrade to a release after 8.0
Vendor patch github.com →
Recommended fix Moderate confidence

Proxmox VE 8.1+, Proxmox Backup Server 3.1+, Proxmox Mail Gateway 8.1+ (or latest available versions)

  1. 1. Identify which Proxmox product(s) are affected in your environment: Proxmox VE, Proxmox Backup Server, or Proxmox Mail Gateway
  2. 2. For Proxmox Virtual Environment: Update to version 8.1 or later by running 'apt update && apt full-upgrade'
  3. 3. For Proxmox Backup Server: Update to version 3.1 or later by running 'apt update && apt full-upgrade'
  4. 4. For Proxmox Mail Gateway: Update to version 8.1 or later by running 'apt update && apt full-upgrade'
  5. 5. After updating, verify the 2FA configuration is working correctly and test the authentication flow
  6. 6. Review user accounts with 2FA to ensure no unauthorized access attempts occurred
  7. 7. Consider reviewing authentication logs for any signs of exploitation prior to patching
Caveat Proxmox major version upgrades may require system reboot and should be tested in staging first; review Proxmox upgrade documentation for specific version migration notes

Generated from the published advisory — verify against the referenced sources before acting.

We can identify the exact fixed release, upgrade, and verify it in staging — typical engagement from $1,950. Get the upgrade done

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2023-43320 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-43320 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