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Patch first › Symantec

Exploited CVE from 2017, added in 2021

CVE-2017-6327

Symantec Messaging Gateway · Email

Symantec Messaging Gateway Remote Code Execution Vulnerability

At a glance

Exploited. Added to CISA’s catalog of exploited vulnerabilities on November 3, 2021.

Affected product: Symantec Messaging Gateway (category Email, indicative classification). Name in CISA’s catalog: Symantec Symantec Messaging Gateway.

What should I do?

Apply the security update from Symantec.

Deadline set by CISA for US federal agencies: 181 days (due May 3, 2022). It only binds those agencies, but it is a useful measure of urgency.

Original text of the required action (CISA)

Apply updates per vendor instructions.

Timeline

  1. Vulnerability published Publication date (NVD)
  2. Exploitation confirmed Added to CISA’s KEV catalog
  3. CISA deadline Remediation deadline set for US federal agencies

The facts, with their sources

Exploitation confirmed
Yes, on November 3, 2021 Date added to the catalog of exploited vulnerabilities. Exploitation itself may have started earlier. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Ransomware
No known use to date That does not guarantee it is not being used: the information is not public. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Hunt for compromise
Not requested by CISA Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CISA required action
Apply the security update from Symantec. Rewritten by this site from CISA’s original text. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CISA deadline
May 3, 2022, 181 days Set for US federal agencies: a measure of urgency, not an obligation elsewhere. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Vulnerability published
August 11, 2017 Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC
Product according to CISA
Symantec Symantec Messaging Gateway Filed by this site under “Email” (indicative classification). Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Technical detail of the score: attack vector, complexity, impact. Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC

Severity and activity

8.8 / 10 CVSS severity: high

Score from the NVD. Collected Sep 29, 2026.

— Probability of exploitation in the next 30 days (EPSS)

FIRST’s EPSS model. Since exploitation is already confirmed, this figure is mostly useful to compare activity. Collected Sep 29, 2026.

Description

The Symantec Messaging Gateway before 10.6.3-267 can encounter an issue of remote code execution, which describes a situation whereby an individual may obtain the ability to execute commands remotely on a target machine or in a target process. In this type of occurrence, after gaining access to the system, the attacker may attempt to elevate their privileges.

Official description from the NVD, collected Sep 29, 2026. CVE® description © The MITRE Corporation.

Symantec Messaging Gateway contains an unspecified vulnerability which can allow for remote code execution. With the ability to perform remote code execution, an attacker may also desire to perform privilege escalating actions.

Summary from CISA (KEV catalog).

CERT-FR advisories

No advisory among the latest CERT-FR publications this site follows. That does not mean there are none.

Information reused under the Open Licence 2.0 (Etalab); the date of last update is shown for each advisory. This site is neither affiliated with nor endorsed by ANSSI.

Sources for this page

  • CISA KEV catalog: exploitation, date added, required action, deadline, ransomware.
  • NVD (NIST): CVSS severity, publication date, description, vendor references.
  • EPSS (FIRST): probability of exploitation.
  • CERT-FR: advisories and alerts (in French).
  • Brand and category: indicative classification by this site (method).