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CVE-2014-6271

Critical 9.8 Exploited in the wild (KEV)

Confirmed active exploitation — CISA KEV catalog

Name
GNU Bourne-Again Shell (Bash) Arbitrary Code Execution Vulnerability
Added to catalog
Remediation due date (US federal)
Required action
Apply updates per vendor instructions.

Description

GNU Bash through 4.3 processes trailing strings after function definitions in the values of environment variables, which allows remote attackers to execute arbitrary code 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, aka "ShellShock." NOTE: the original fix for this issue was incorrect; CVE-2014-7169 has been assigned to cover the vulnerability that is still present after the incorrect fix.

Metrics

CVSS 3.1
9.8 (CRITICAL) Score source: NVD CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS — exploit probability
100% (percentile: 100) as of 1 November 2026
CWE
CWE-78

Affected products

gnu: bash; arista: eos; oracle: linux; qnap: qts; mageia: mageia; redhat: gluster storage server for on-premise; redhat: virtualization; redhat: enterprise linux; redhat: enterprise linux desktop; redhat: enterprise linux eus; redhat: enterprise linux for ibm z systems; redhat: enterprise linux for power big endian; redhat: enterprise linux for power big endian eus; redhat: enterprise linux for scientific computing; redhat: enterprise linux server

References