Is CVE-2021-41816 in the CISA KEV catalog?

No. CVE-2021-41816 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-41816?

CVE-2021-41816 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2021-41816?

CVE-2021-41816 has an EPSS score of 4.77% (91th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-41816?

Upgrade ruby2.7 on debian 11 to 2.7.4-1+deb11u1 or later. Fixes are available for 4 affected products.

CVE & CISA-KEV Catalog

CVE-2021-41816

CRITICALEPSS 91th pctl

9.8

CVSS v3

NVD

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.

CWE-190Integer Overflow

How to fix

Remediation Available

ruby2.7Debian

Fixed in:2.7.4-1+deb11u1CVE-2021-41816

ruby2.3Ubuntu

Fixed in:2.3.1-2~ubuntu16.04.16+esm2USN-5235-1

ruby2.5Ubuntu

Fixed in:2.5.1-1ubuntu1.11USN-5235-1

ruby2.7Ubuntu

Fixed in:2.7.0-5ubuntu1.6USN-5235-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

4.77%probability of exploitation in 30 days

91stpercentile

High risk: more likely to be exploited than 91% of all known CVEs.

References

Exploit1

ruby-lang.org

Third-Party Advisory3

Other references3

Related Vulnerabilities

Other CWE-190 (Integer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2020-16040	Medium	6.5	100%	-	Fix
CVE-2019-11477	High	7.5	99%	-	Fix
CVE-2023-44443	High	7.8	94%	-	Fix
CVE-2014-0569	High	9.3	90%	-	-
CVE-2017-3599	High	7.5	90%	-	Fix
CVE-2023-21716	Critical	9.8	82%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.