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CVE-2014-6271 CISA KEV — actively exploited

GNU Bourne-Again Shell (Bash) Arbitrary Code Execution Vulnerability

n/a — n/a

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.

CVSS scoreCritical

9.8

EPSS — exploitation probabilityCritical

100.0%

Vector breakdown

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Published
Sep 24, 2014
Modified
Jun 17, 2026
Added to KEV
Jan 28, 2022
Federal patch due
Jul 28, 2022

CISA required action

Apply updates per vendor instructions.

Weakness classification

CWE-78Improper Neutralization of Special Elements used in an OS Command

Affected packages

unknown packageunknown
GHSA-6hfc-grwp-2p9c

Proof-of-concept & exploitation references

8 found

Weaponization

Nuclei template

Available

Metasploit module

Not found

Public repositories whose name or description references CVE-2014-6271, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit — cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.

References

How this class of flaw gets exploited

Frequently asked questions

What is CVE-2014-6271?

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.

How severe is CVE-2014-6271?

CVE-2014-6271 has a CVSS base score of 9.8 out of 10 (CVSS 3.1).

Is CVE-2014-6271 actively exploited in the wild?

Yes. CVE-2014-6271 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Jan 28, 2022, meaning CISA has confirmed evidence of active exploitation.

What is the EPSS score for CVE-2014-6271?

100.0% - meaning FIRST.org's EPSS model estimates a 100.0% probability this vulnerability will be exploited in the wild within 30 days (100% percentile among all scored CVEs).

Is there exploit tooling available for CVE-2014-6271?

Yes - a public Nuclei template referencing CVE-2014-6271 exist in public repositories we checked. We also found 8 public GitHub repositories referencing this CVE.

What type of vulnerability is CVE-2014-6271?

CVE-2014-6271 is classified under CWE-78 (CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')).

Cross-checked against

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