---
id: "CVE-2014-7169"
kind: "vulnerability"
aliases: ["CVE-2014-7169"]
title: "GNU Bourne-Again Shell (Bash): GNU Bourne-Again Shell (Bash) Arbitrary Code Execution Vulnerability"
severity: "critical"
cvss: 10.0
epss: 0.9994
exploited: true
status: "open"
category: "runtime"
products: [{"name": "GNU Bourne-Again Shell (Bash)", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["bash", "cgi", "dhcp", "exploited", "linux", "runtime", "self-hosted"]
not_affected_if: ["managed-hosting", "no-bash-in-path", "patched-bash"]
published_at: "2014-09-25T01:55:04+00:00"
first_seen_at: "2026-10-23T19:11:53+00:00"
updated_at: "2026-10-23T21:57:35+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2014-7169", "first_seen_at": "2026-10-23T19:11:53+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2014-7169", "first_seen_at": "2026-10-23T19:13:44+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2014-7169", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

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

GNU Bash through 4.3 executes trailing commands hidden after function definitions in environment variable values, so a remote attacker who can set an environment variable reaches code execution. This is the incomplete fix to Shellshock (CVE-2014-6271) and is listed as actively exploited.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:GNU Bourne-Again Shell (Bash) affected ? fixed ?

## How to check

Run: bash --version and compare against the patched release from your OS vendor.
Test: env 'x=() { :;}; echo VULNERABLE' bash -c 'echo test' (prints VULNERABLE when unpatched).
Check whether CGI scripts or DHCP clients pass HTTP headers into environment variables.

## Fix

Update bash to the patched package from your OS vendor (Bash 4.3 patch 25 or later is the upstream fix level) and restart services that spawn bash.
Re-run the env test above after patching to confirm.

## Timeline

- 2026-10-23T19:11:53+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2014-7169
- 2026-10-23T19:13:44+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2014-7169
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2014-7169

## From the sources

GNU Bash through 4.3 bash43-025 processes trailing strings after certain malformed function definitions in the values of environment variables, which allows remote attackers to write to files or possibly have unknown other impact 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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_