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UK Cyber Defence
VulnerabilityAnalyzed

CVE-2014-6278

GNU Bash OS Command Injection Vulnerability

KEVHIGH 8.8EPSS 99.5%

Does this matter?

Known to be exploited in the wild (CISA KEV, CISA remediation deadline 23 October 2025). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.

Description

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 3.1
8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS
99.52% probability · 100th percentile
CISA KEV
Listed 2 October 2025 · due 23 October 2025
Weakness
CWE-78
Affected
gnu/bash
Source
security@debian.org

CISA notes

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. This vulnerability could affect an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: http://ftp.gnu.org/gnu/bash/bash-4.3-patches/bash43-027 ; https://support.broadcom.com/web/ecx/support-content-notification/-/external/content/SecurityAdvisories/0/23467 ; https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20140926-bash ; https://www.ibm.com/support/pages/security-bulletin-update-vulnerabilities-bash-affect-aix-toolbox-linux-applications-cve-2014-6271-cve-2014-6277-cve-2014-6278-cve-2014-7169-cve-2014-7186-and-cve-2014-7187 ; https://nvd.nist.gov/vuln/detail/CVE-2014-6278

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.