How severe is CVE-2018-12242?

CVE-2018-12242 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-12242 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-12242?

CVE-2018-12242 affects Symantec Messaging Gateway. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-12242?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2018-12242 published?

CVE-2018-12242 was published on 2018-09-19 and last updated on 2026-06-17.

CVE-2018-12242

CVE-2018-12242 is a critical-severity vulnerability in Symantec Messaging Gateway with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 3% (86th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Symantec Messaging Gateway
Published: 2018-09-19
Last modified: 2026-06-17

Description

The Symantec Messaging Gateway product prior to 10.6.6 may be susceptible to an authentication bypass exploit, which is a type of issue that can allow attackers to potentially circumvent security mechanisms currently in place and gain access to the system or network.

Frequently asked questions

What is CVE-2018-12242?: The Symantec Messaging Gateway product prior to 10.6.6 may be susceptible to an authentication bypass exploit, which is a type of issue that can allow attackers to potentially circumvent security mechanisms currently in place and gain access to the system or network.
How severe is CVE-2018-12242?: CVE-2018-12242 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-12242 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-12242?: CVE-2018-12242 affects Symantec Messaging Gateway. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-12242?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2018-12242 published?: CVE-2018-12242 was published on 2018-09-19 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:symantec:messaging_gateway:*:*:*:*:*:*:*:*

More vulnerabilities in Symantec Messaging Gateway

CVE-2017-6326 — Critical (CVSS 10.0): The Symantec Messaging Gateway can encounter an issue of remote code execution, which describes a situation whereby an…
CVE-2018-12243 — High (CVSS 8.8): The Symantec Messaging Gateway product prior to 10.6.6 may be susceptible to a XML external entity (XXE) exploit, which…
CVE-2016-2204 — High (CVSS 8.2): The management console on Symantec Messaging Gateway (SMG) Appliance devices before 10.6.1 allows local users to obtain…
CVE-2012-3579 — High (CVSS 7.9): Symantec Messaging Gateway (SMG) before 10.0 has a default password for an unspecified account, which makes it easier…
CVE-2012-6277 — High (CVSS 7.8): Multiple unspecified vulnerabilities in Autonomy KeyView IDOL before 10.16, as used in Symantec Mail Security for…
CVE-2016-2203 — High (CVSS 7.8): The management console on Symantec Messaging Gateway (SMG) Appliance devices before 10.6.1 allows local users to…

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Other CWE-287 (Improper Authentication) vulnerabilities

CVE-2026-45480 — Critical (CVSS 10.0): Improper authentication in Azure Active Directory allows an unauthorized attacker to elevate privileges over a network.
CVE-2026-46389 — Critical (CVSS 10.0): UDS Identity Config builds the Keycloak configuration image (realm, plugins, theme, truststore, JARs) consumed by UDS…
CVE-2026-10611 — Critical (CVSS 10.0): An authentication bypass vulnerability exists in MISP when LDAP mixed authentication is enabled with OTP enforcement.…
CVE-2026-47280 — Critical (CVSS 10.0): Improper authentication in Azure Resource Manager (ARM) allows an unauthorized attacker to elevate privileges over a…
CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
CVE-2026-20182 — Critical (CVSS 10.0): May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and…

Browse all CWE-287 (Improper Authentication) vulnerabilities →