CVE-2009-4492

CVE-2009-4492 is a high-severity vulnerability in Ruby-lang Webrick with a CVSS 2.0 base score of 7.5. Its EPSS exploit-prediction score of 16% places it in the 96th percentile, indicating an elevated likelihood of exploitation.

Key facts

Description

WEBrick 1.3.1 in Ruby 1.8.6 through patchlevel 383, 1.8.7 through patchlevel 248, 1.8.8dev, 1.9.1 through patchlevel 376, and 1.9.2dev 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.

Frequently asked questions

What is CVE-2009-4492?
WEBrick 1.3.1 in Ruby 1.8.6 through patchlevel 383, 1.8.7 through patchlevel 248, 1.8.8dev, 1.9.1 through patchlevel 376, and 1.9.2dev 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.
How severe is CVE-2009-4492?
CVE-2009-4492 has a CVSS 2.0 base score of 7.5, rated high severity.
Is CVE-2009-4492 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 16% (96th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-4492?
CVE-2009-4492 affects Ruby-lang Webrick. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2009-4492?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2009-4492 published?
CVE-2009-4492 was published on 2010-01-13 and last updated on 2026-06-16.

References

Affected products (1)

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