CVE-2014-6271
CRITICALCVE-2014-6271 is a critical-severity (CVSS 9.8) OS Command Injection vulnerability. 79 public exploit references exist, so weaponization risk is real. O3 Security confirms whether CVE-2014-6271 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Exploitation Status
Actively exploited in the wild
- CISA’s SSVC triage classifies this CVE as under active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2014-6271.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2014-6271 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE sits: patch-first territory.
Where this sits among everything scored
Of 368,770 CVEs with a current EPSS score, this one falls in the ≥ 90% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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.
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Bash CGI - 'Shellshock' Remote Command Injection (Metasploit)
by Fady Mohammed Osman · Oct 6, 2014
GNU bash 4.3.11 - Environment Variable dhclient
by @0x00string · Oct 2, 2014
CUPS Filter - Bash Environment Variable Code Injection (Metasploit)
by Metasploit · Oct 29, 2014
Apache mod_cgi - 'Shellshock' Remote Command Injection
by Federico Galatolo · Oct 6, 2014
RedStar 3.0 Server - 'Shellshock' 'BEAM' / 'RSSMON' Command Injection
by Hacker Fantastic · Dec 18, 2016
IPFire - 'Shellshock' Bash Environment Variable Command Injection (Metasploit)
by Metasploit · Jun 10, 2016
Qmail SMTP - Bash Environment Variable Injection (Metasploit)
by Metasploit · Oct 2, 2017
GNU Bash - Environment Variable Command Injection (Metasploit)
by Shaun Colley · Sep 25, 2014
PHP < 5.6.2 - 'Shellshock' Safe Mode / disable_functions Bypass / Command Injection
by Ryan King (Starfall) · Nov 3, 2014
Advantech Switch - 'Shellshock' Bash Environment Variable Command Injection (Metasploit)
by Metasploit · Dec 2, 2015
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2014-6271 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2014-6271 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2014-6271. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Frequently Asked Questions
Is CVE-2014-6271 in your dependencies?
O3 detects CVE-2014-6271 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.