CVE-2014-6278
Published: 30 September 2014
Summary
CVE-2014-6278 is a high-severity OS Command Injection (CWE-78) vulnerability in Gnu Bash. Its CVSS base score is 8.8 (High).
Operationally, ranked in the top 0.3% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).
Deeper analysis
GNU Bash through 4.3 bash43-026 does not properly parse function definitions in the values of environment variables. The affected component is the Bash shell itself, and the issue is explicitly noted as resulting from an incomplete fix for CVE-2014-6271, CVE-2014-7169, and CVE-2014-6277. The weakness is classified under CWE-78.
Remote attackers can supply a crafted environment to execute arbitrary commands. Exploitation is feasible across privilege boundaries in scenarios that include the ForceCommand feature in OpenSSH sshd, the mod_cgi and mod_cgid modules in the Apache HTTP Server, scripts run by unspecified DHCP clients, and similar situations where environment variables are populated before Bash executes.
The vulnerability carries a CVSS 3.1 base score of 8.8 with an attack vector of network, low complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2014-6163
Vulnerability details
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,…
more
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.
- CWE(s)
- KEV Date Added
- 02 October 2025
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly counters CWE-78 OS command injection by requiring validation/sanitization of untrusted environment-variable values before they reach Bash.
Mandates prompt application of patches that complete the incomplete fixes for CVE-2014-6271/7169/6277 and eliminate the parser flaw in Bash.
Restricts use of Bash (or specific features such as ForceCommand, mod_cgi) to only those essential functions, reducing the attack surface across privilege boundaries.