Skip to content
Weekly Signal
Live intelligence Updated 19 Aug 2026 · 20:27 UTC

Apple, Arista, Canonical +14 more · Mac Os X, Eos, Ubuntu Linux +72 more

CVE-2014-6271

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

Recommended action

Treat this as an immediate remediation priority. Apply updates per vendor instructions.

View response plan
CVSS9.8
EPSS100.0%
KEVYes
ExploitationConfirmed exploitation
PatchPatch or guidance available ↓

Assessment

Why it matters

CISA lists this vulnerability as known to be exploited; exploitation is confirmed; EPSS is 100.0%; technical severity is CVSS 9.8.

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.

Who should care

  • Teams operating Mac Os X, Eos, Ubuntu Linux +72 more
  • Vulnerability and exposure management teams
  • Security operations teams monitoring exploitation activity

Response plan

What I would do

  1. Confirm whether Mac Os X, Eos, Ubuntu Linux +72 more is present in the environment.
  2. Identify affected versions and establish whether vulnerable services are exposed or reachable.
  3. Apply updates per vendor instructions.
  4. Review relevant security telemetry for evidence of attempted or successful exploitation.
  5. Document the remediation decision and track it to verified completion.

Vendor remediation

Patch and remediation links

Use the vendor source below to confirm the correct fixed version, package or mitigation for your affected product.

Technical details

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-78
Affected versions
Apple Mac Os X (Start Including: 10.0.0, End Excluding: 10.10.0); Arista Eos (Start Including: 4.14.0, End Excluding: 4.14.4f); Canonical Ubuntu Linux (Version: 14.04); Checkpoint Security Gateway (End Excluding: r77.30); Citrix Netscaler Sdx Firmware (Start Including: 10.5, End Excluding: 10.5.52.11r1); Debian Debian Linux (Version: 7.0); F5 Arx Firmware (Start Including: 6.0.0, End Including: 6.4.0); F5 Big-ip Access Policy Manager (Version: 11.6.0)
Published
24 September 2014
Attack vector
Network
Privileges required
None
User interaction
None

Signal timeline

  1. CVE published
  2. Added to CISA KEV
  3. Latest EPSS score: 100.0%
  4. Signal calculated at 85

External references

Live public intelligence This assessment combines public-source evidence. Validate the affected product, version and exposure against your own environment before making a risk decision.