Port 5318Certificate Management over CMS (CMC)

Certificate enrollment and management messages using CMS, typically exchanged between PKI clients and certificate authorities.

inSecurity Network Services

transport: tcp
in transit: cleartext
assignment: official
risk: 2/10
lookups: 0

also known as pkix-cmc, CMC

Technical Details

what runs on :5318

CMC carries certificate-management operations in ASN.1 CMS structures, including client requests and CA responses. The protocol is transport-independent; TCP port 5318 is its registered endpoint, but the port alone does not guarantee a particular message framing or indicate that HTTP or TLS is in use. CMC can also be transported using mechanisms such as HTTP, and its CMS messages may be signed without being encrypted.

Security Information

exposure of :5318

risk score

2/ 10safe

routine exposure. this port is rarely the way in on its own — keep it patched and logged and move on.

security averages 3.0 across 388 ports — this one sits 1.0 below.

in transit

cleartext

credentials and payloads are readable by anyone on path

assignment

official

registered with iana for this service — scanners fingerprint it by number

reachable over

tcp

every listening transport is another surface to filter at the edge

security overview

A CMC endpoint can expose sensitive certificate issuance or revocation functions, so access should be limited to intended PKI clients and operations protected by appropriate authentication and authorization. CMS signatures and proof-of-possession help authenticate requests but do not by themselves encrypt traffic; use a protected transport where confidentiality is required. Public exposure is unusual and should be reviewed as part of the CA's security boundary.

Record

iana registry entry

port: :5318
service: Certificate Management over CMS (CMC)
transport: TCP
encryption: cleartext
assignment: iana registered
risk: 2/10safe
category: Security Network Services
usage: Port 5318 is assigned to CMC, a standards-based protocol for PKI operations such as certificate enrollment and revocation. It is uncommon on public networks; where deployed, it is generally part of a certificate authority or registration-authority workflow.
lookups: 0rank 993
added: 2026-10-07
updated: 2026-10-07
references: IANA service name registry — port 5318
RFC 10003

Something wrong?

This record is maintained by the engineers who use port 5318. Every field on it is editable — change what's wrong, say how you know, and a reviewer publishes it, usually within a minute. Last touched 2026-10-07.

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risk mix of the 8 listed

caution100%

2 of 8 encrypted

Port :5318Certificate Management over CMS (CMC)

Technical Details

Security Information

Related Ports

Port 5318Certificate Management over CMS (CMC)