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IMMUNITYSEC

Shellshock (CVE-2014-6271)

9.8
CRITICAL
CVSS 3.1
EPSS 100.0% · 100th pctCISA KEV · Exploited in the wild
2014-09-24Updated 2025-10-22KEV 2022-01-28
CISA Known Exploited Vulnerabilities

GNU Bourne-Again Shell (Bash) Arbitrary Code Execution Vulnerability is confirmed as actively exploited and is listed in the CISA KEV catalog.

Added to KEV
2022-01-28
Remediation due
2022-07-28

Required action
Apply updates per vendor instructions.

CISA notes
https://nvd.nist.gov/vuln/detail/CVE-2014-6271

Also Known as Shellshock

Shellshock is the name for a GNU Bash flaw, disclosed in September 2014, in which text after a function definition in an environment variable is executed. CISA's alert applies the name to CVE-2014-6271 and to several follow-up Bash CVEs filed for incomplete fixes.

Name sources

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.

Severity

CVSS 3.1 · CISA9.8 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC · CISA-ADP
Exploitationactive
Automatableyes
Technical impacttotal

Exploitation Context

as of October 13, 2026
All KEV statistics→
  • CISA added CVE-2014-6271 to the KEV catalog 2,683 days after its CVE record was published.
  • It is one of 5 GNU entries in the CISA KEV catalog, and one of 2 added in 2022.
  • Its current EPSS score (100.0%) is higher than that of 97% of CISA KEV entries.

Affected Products

ProductAffected versions
-
n/a

References

170 Links
Vulnerability databases
Other references

Record Details

Published
2014-09-24
Last updated
2025-10-22
Assigner (CNA)
debian
Credited to
-

CVE record data © The MITRE Corporation, used under the CVE Terms of Use. Exploited-in-the-wild data from the CISA Known Exploited Vulnerabilities catalog (CC0). Exploit prediction scores by FIRST EPSS (first.org/epss). This site is not endorsed or certified by MITRE, NVD, CISA, or FIRST.