Is CVE-2021-43797 in the CISA KEV catalog?

No. CVE-2021-43797 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-43797?

CVE-2021-43797 has a CVSS v3 base score of 6.5 (MEDIUM).

What is the EPSS score for CVE-2021-43797?

CVE-2021-43797 has an EPSS score of 2.68% (84th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-43797?

Upgrade netty on debian 11 to 1:4.1.48-4+deb11u1 or later. Fixes are available for 3 affected products.

CVE & CISA-KEV Catalog

CVE-2021-43797

MEDIUMEPSS 84th pctl

6.5

CVSS v3

NVD

Description

Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. Netty prior to version 4.1.71.Final skips control chars when they are present at the beginning / end of the header name. It should instead fail fast as these are not allowed by the spec and could lead to HTTP request smuggling. Failing to do the validation might cause netty to "sanitize" header names before it forward these to another remote system when used as proxy. This remote system can't see the invalid usage anymore, and therefore does not do the validation itself. Users should upgrade to version 4.1.71.Final.

CWE-444

How to fix

Remediation Available

nettyDebian

Fixed in:1:4.1.48-4+deb11u1CVE-2021-43797

Fixed in:1:4.1.48-6CVE-2021-43797

libnetty-javaUbuntu

Fixed in:1:4.0.34-1ubuntu0.1~esm1USN-6049-1

Fixed in:1:4.1.7-4ubuntu0.1+esm2USN-6049-1

Fixed in:1:4.1.45-1ubuntu0.1~esm1USN-6049-1

Fixed in:1:4.1.48-4+deb11u1build0.22.04.1USN-6049-1

Fixed in:1:4.1.48-5ubuntu0.1USN-6049-1

nettyUbuntu

Fixed in:1:4.0.34-1ubuntu0.1~esm1USN-6049-1

Fixed in:1:4.1.7-4ubuntu0.1+esm2USN-6049-1

Fixed in:1:4.1.45-1ubuntu0.1~esm1USN-6049-1

Fixed in:1:4.1.48-4+deb11u1build0.22.04.1USN-6049-1

Fixed in:1:4.1.48-5ubuntu0.1USN-6049-1

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 InteractionRequired

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityHigh

AvailabilityNone

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

Exploit Intelligence

2.68%probability of exploitation in 30 days

84thpercentile

Elevated risk: more likely to be exploited than 84% of all known CVEs.

References

Patch3

Third-Party Advisory4

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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.