CVE-2009-4488: Varnish.projects.linpro Varnish

Critical severity, CVSS 9.8. EPSS: 13% chance of exploitation in the next 30 days.

Varnish 2.0.6 writes data to a log file without sanitizing non-printable characters, which might allow remote attackers to modify a window's title, or possibly execute arbitrary commands or overwrite files, via an HTTP request containing an escape sequence for a terminal emulator. NOTE: the vendor disputes the significance of this report, stating that "This is not a security problem in Varnish or any other piece of software which writes a logfile. The real problem is the mistaken belief that you can cat(1) a random logfile to your terminal safely.

Affected products

Published 2010-01-13. Last modified 2026-06-16.