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HIGH · CVSS 8.8 CISA Known Exploited Vulnerability

CVE-2014-6278

GNU Bash OS Command Injection Vulnerability

GNU Bash

GNU Bash through 4.3 bash43-026 does not properly parse function definitions in the values of environment variables, which allows remote attackers to execute arbitrary commands via a crafted environment, as demonstrated by vectors involving the ForceCommand feature in OpenSSH sshd, the mod_cgi and mod_cgid modules in the Apache HTTP Server, scripts executed by unspecified DHCP clients, and other situations in which setting the environment occurs across a privilege boundary from Bash execution. NOTE: this vulnerability exists because of an incomplete fix for CVE-2014-6271, CVE-2014-7169, and CVE-2014-6277.

CVSS
8.8
HIGH
EPSS
99.7%
30-day exploitation
Ransomware groups
0
recorded exploiting
Published
30 Sep 2014
CWE-78

Exploitation status

CISA Known Exploited Vulnerabilities

Listed by CISA on 2 October 2025. US federal agencies were required to remediate it by 23 October 2025.

EPSS — exploitation probability

FIRST puts the probability of exploitation activity in the next 30 days at 99.7%, which is higher than 99.9% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Frequently asked questions

Is CVE-2014-6278 being exploited by ransomware groups?

No ransomware group in this database is currently recorded as exploiting CVE-2014-6278.

What does CVE-2014-6278 affect?

CVE-2014-6278 affects GNU Bash. GNU Bash through 4.3 bash43-026 does not properly parse function definitions in the values of environment variables, which allows remote attackers to execute arbitrary commands via a crafted environment, as demonstrated by vectors involving the ForceCommand feature in OpenSSH sshd, the mod_cgi and mod_cgid modules in the Apache HTTP Server, scripts executed by unspecified DHCP clients, and other situations in which setting the environment occurs across a privilege boundary from Bash execution. NOTE: this vulnerability exists because of an incomplete fix for CVE-2014-6271, CVE-2014-7169, and CVE-2014-6277.

How severe is CVE-2014-6278?

CVE-2014-6278 is rated HIGH with a CVSS base score of 8.8. EPSS puts the probability of exploitation in the next 30 days at 99.7%, higher than 99.9% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 23 October 2025.

How should organisations respond to CVE-2014-6278?

Apply the vendor patch for GNU Bash as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.