WebORB for Java by Midnight Coders, version 5.1.1.0, Action Message Format (AMF3) Java implementation is vulnerable to insecure deserialization

published 2018-06-11 8 y ago modified 2026-06-17 4 mo ago also EUVD-2017-12328

cvss: 9.8; version 3.0, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 8.1%; EPSS 8.1% chance of exploitation in 30 days, percentile 94%
public exploits: 0; none known

The Java implementations of AMF3 deserializers in WebORB for Java by Midnight Coders, version 5.1.1.0, derive class instances from java.io.Externalizable rather than the AMF3 specification's recommendation of flash.utils.IExternalizable. A remote attacker with the ability to spoof or control an RMI server connection may be able to send serialized Java objects that execute arbitrary code when deserialized.

Exploit prediction

8.08% chance of exploitation in the next 30 days, higher than 94% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

codewhitesec.blogspot.com https://codewhitesec.blogspot.com/2017/04/amf.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.0	9.8	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	7.5	AV:N/AC:L/Au:N/C:P/I:P/A:P

Affected products

Midnight Coders WebORB for Java

Classification

Weakness

CWE-502 Deserialization of Untrusted Data

References

codewhitesec.blogspot.com /2017/04/amf.html
exploit, third-party-advisory
kb.cert.org /vuls/id/307983
third-party-advisory, us-government-resource
securityweek.com /flaws-java-amf-libraries-allow-remote-code-execution
third-party-advisory
securityfocus.com /bid/97384
vdb-entry, third-party-advisory

Sources

CVE List CVE-2017-3207
NVD CVE-2017-3207

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary