Is CVE-2021-39242 in the CISA KEV catalog?

No. CVE-2021-39242 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-39242?

CVE-2021-39242 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2021-39242?

CVE-2021-39242 has an EPSS score of 2.34% (82th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-39242?

Upgrade haproxy on debian 11 to 2.2.9-2+deb11u1 or later.

CVE & CISA-KEV Catalog

CVE-2021-39242

HIGHEPSS 82th pctl

7.5

CVSS v3

NVD

Description

An issue was discovered in HAProxy 2.2 before 2.2.16, 2.3 before 2.3.13, and 2.4 before 2.4.3. It can lead to a situation with an attacker-controlled HTTP Host header, because a mismatch between Host and authority is mishandled.

CWE-755

How to fix

Remediation Available

haproxyDebian

Fixed in:2.2.9-2+deb11u1CVE-2021-39242

Fixed in:2.2.16-1CVE-2021-39242

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

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

ConfidentialityNone

IntegrityHigh

AvailabilityNone

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

Exploit Intelligence

2.34%probability of exploitation in 30 days

82ndpercentile

Elevated risk: more likely to be exploited than 82% of all known CVEs.

References

Third-Party Advisory1

debian.org

Other references4

Related Vulnerabilities

Other CWE-755 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2017-5638	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2020-7247	Critical	9.8	99%	KEV	Fix
CVE-2023-36933	High	7.5	72%	-	Fix
CVE-2018-0934	High	7.5	66%	-	Fix
CVE-2019-14287	High	8.8	64%	-	Fix
CVE-2019-12815	Critical	9.8	58%	-	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.