CVE-2007-6509: Appian BPM Suite crafted packet on port 5400 causes denial of service

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 19 September 2026. Confidence: medium.

high priorityUnauthenticated remote availability impact with a high EPSS score, though no KEV listing or confirmed in-the-wild exploitation is documented.

What it is

Appian Enterprise BPM Suite 5.6 SP1 contains an unspecified input validation flaw reachable over TCP port 5400. A remote attacker can send a crafted packet that crashes or exhausts the service, denying availability. The record gives no root-cause detail beyond CWE-20, so the exact malformed input is unknown.

Impact

An unauthenticated remote attacker can cause a denial of service, taking the BPM service offline for legitimate users. No confidentiality or integrity impact is indicated; the CVSS vector is availability-only.

Attack surface

Reachable over the network via TCP port 5400; the CVSS vector AV:N/AC:L/Au:N indicates no authentication and no user interaction are required. The crafted packet is sent directly to the listening service.

Exploitation

Not listed in CISA KEV and no ransomware association is documented. EPSS is high (0.55, ~99th percentile), suggesting elevated predicted exploitation activity, but no public exploit or in-the-wild confirmation is stated in the record.

What to do

• Apply the vendor fix for Appian Enterprise BPM Suite 5.6 SP1; check Appian advisories and support channels for the patched build, as the record does not name a fixed version.
• Restrict network access to TCP port 5400 to trusted hosts or management networks using firewall or ACL rules.
• Place the BPM service behind a reverse proxy or filtering device that can drop malformed traffic to port 5400.
• Monitor the service for crash/restart loops and rate-limit connections to port 5400 from untrusted sources.
• If no patch is available, isolate the affected instance and treat port 5400 as untrusted until it can be upgraded.

Detection

• Alert on repeated connection attempts or malformed packets to TCP port 5400 from external or unexpected sources.
• Monitor Appian BPM service process crashes, restarts, or availability gaps correlated with inbound port 5400 traffic.
• Baseline normal port 5400 traffic and flag spikes in connection volume or packet size anomalies.
• Review firewall and IDS logs for scanning or probing of port 5400 across the environment.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.