CVE-2018-12243

The Symantec Messaging Gateway product prior to 10.6.6 may be susceptible to a XML external entity (XXE) exploit, which is a type of issue where XML input containing a reference to an external entity is processed by a weakly configured XML parser. The attack uses file URI schemes or relative paths in the system identifier to access files that should not normally be accessible.

Published: 2018-09-19 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-12243 is rated Moderate Risk (53.4/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.77%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2018-12243

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.23% 0.77% +0.54%
2 2025-03-30 0.57% 0.23% -0.34%
3 2025-03-29 — 0.57% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-12243

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.0 HIGH
CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:A)
Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
5.8 2.0 MEDIUM
AV:A/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:A)
Requires access to an adjacent network segment.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 6.5 6.4 [email protected]

Weakness enumeration for CVE-2018-12243

Affected software / configurations for CVE-2018-12243

Vendor Product Version Raw CPE
symantec messaging_gateway < 10.6.6 cpe:2.3:a:symantec:messaging_gateway:*:*:*:*:*:*:*:*

References for CVE-2018-12243

URL Tags
http://www.securityfocus.com/bid/105330 Third Party Advisory VDB Entry
https://support.symantec.com/en_US/article.SYMSA1461.html Mitigation Vendor Advisory
cvelogic Threat Intelligence