CVE-2021-41816
CVSS v3
9.8
CRITICAL
EPSS Score
4.8 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
CGI.escape_html in Ruby before 2.7.5 and 3.x before 3.0.3 has an integer overflow and resultant buffer overflow via a long string on platforms (such as Windows) where size_t and long have different numbers of bytes. This also affects the CGI gem before 0.3.1 for Ruby.
Technical details
- Published
- 2022-02-06
Frequently asked questions
What is CVE-2021-41816?
CGI.escape_html in Ruby before 2.7.5 and 3.x before 3.0.3 has an integer overflow and resultant buffer overflow via a long string on platforms (such as Windows) where size_t and long have different numbers of bytes. This also affects the CGI gem before 0.3.1 for Ruby.
Is CVE-2021-41816 actively exploited?
Active exploitation of CVE-2021-41816 has not been confirmed. Its EPSS score was 4.8% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2021-41816?
CVE-2021-41816 has a CVSS v3 base score of 9.8 (CRITICAL severity).
Is CVE-2021-41816 affecting your environment?
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