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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 29 Nov 2023.
EsxiOperating system · VMware

CVE-2023-29552

HIGH · 7.5 CVSS v3.1 Published 2023-04-25
Fix available
A fix is available. Upgrade to 7.0 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild High EPSS Public exploit Remotely reachable No privileges 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 Service Location Protocol (SLP, RFC 2608) allows an unauthenticated, remote attacker to register arbitrary services. This could allow the attacker to use spoofed UDP traffic to conduct a denial-of-service attack with a significant amplification factor.

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

The Service Location Protocol (SLP, RFC 2608) contains a vulnerability allowing unauthenticated, remote attackers to register arbitrary services. Attackers can exploit this to conduct amplified denial-of-service attacks using spoofed UDP traffic, leveraging SLP's default UDP port 427 and the protocol's design for service discovery.

MitigationDisable SLP on systems where it is not required, or restrict access by blocking UDP port 427 at network firewalls. Implement ingress filtering to prevent IP spoofing to mitigate the amplification attack vector.

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
EsxiOperating system
Affected:< 7.0
Smi S ProviderApplication
Affected:all versions
Manager ServerApplication
Affected:all versions
Linux Enterprise ServerOperating system
Affected:= 11= 12= 15
Service Location ProtocolApplication
Affected:all versions

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
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

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

  1. Confirm SLP service is running
    Check if the Service Location Protocol service is active on the system. On Linux systems, run 'systemctl status slpd' or check for processes listening on UDP port 427 using 'netstat -uan | grep 427' or 'ss -uan | grep 427'. On VMware ESXi, check via 'esxcli system slp status'.
    Affected if SLP service is running and listening on UDP port 427, making the service registration function accessible to network attackers.
  2. Verify UDP port 427 is exposed
    Scan the system or check listening ports for UDP port 427. Use 'nmap -sU -p 427 <target>' or verify with 'ss -lunp | grep 427' to confirm the port is bound and accessible from the network.
    Affected if UDP port 427 is open and listening, allowing external attackers to send SLP service registration requests to the system.
  3. Check installed product version
    For VMware ESXi, run 'vmware -v' or check via 'esxcli system version get'. For Netapp SMI-S Provider, check the installed package version. For SUSE systems, run 'cat /etc/os-release' or 'rpm -q product' to identify the exact version.
    Affected if The installed version falls within the affected ranges: VMware ESXi < 7.0, SUSE Linux Enterprise Server 11/12/15, or any version of Netapp SMI-S Provider, SUSE Manager Server, or the SLP project.
  4. Review SLP configuration for authentication
    Examine the SLP configuration file. On Linux with OpenSLP, check '/etc/slp.conf' or '/etc/slp.reg' for security settings. Look for parameters like 'net.slp.securityEnabled' or 'slp.security' to determine if authentication is enforced. For VMware ESXi, check via 'esxcli system slp config get'.
    Affected if SLP is configured without authentication or with security disabled, allowing unauthenticated attackers to register arbitrary services.
  5. Test for unauthenticated service registration
    If SLP is running and accessible, attempt to send an SLP registration request using tools like 'slptool' or custom UDP packets to port 427 without credentials. Observe if the system accepts and reflects the arbitrary service registration.
    Affected if The system accepts and processes SLP service registrations from unauthenticated sources, confirming the vulnerability is exploitable.

A system is affected if SLP is running with UDP port 427 accessible and the product version matches the affected ranges, particularly any SUSE Linux Enterprise Server 11/12/15, VMware ESXi below 7.0, or any version of Netapp SMI-S Provider or SUSE Manager Server.

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 7.0 or later
Fixed in 7.0
Interim mitigation

Disable SLP on systems where it is not required, or restrict access by blocking UDP port 427 at network firewalls. Implement ingress filtering to prevent IP spoofing to mitigate the amplification attack vector.

Fix this in Esxi Exploited in the wild — priority engagement
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,800
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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-2023-29552 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