Is CVE-2021-39240 in the CISA KEV catalog?

No. CVE-2021-39240 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-39240?

CVE-2021-39240 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2021-39240?

CVE-2021-39240 has an EPSS score of 2.32% (81th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-39240?

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

CVE & CISA-KEV Catalog

CVE-2021-39240

HIGHEPSS 81th 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 does not ensure that the scheme and path portions of a URI have the expected characters. For example, the authority field (as observed on a target HTTP/2 server) might differ from what the routing rules were intended to achieve.

How to fix

Remediation Available

haproxyDebian

Fixed in:2.2.9-2+deb11u1CVE-2021-39240

Fixed in:2.2.16-1CVE-2021-39240

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

IntegrityNone

AvailabilityNone

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

Exploit Intelligence

2.32%probability of exploitation in 30 days

81stpercentile

Elevated risk: more likely to be exploited than 81% of all known CVEs.

References

Third-Party Advisory1

debian.org

Other references5

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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.