CVE-2021-437976.5MediumCWE-444

CVE-2021-43797: HTTP fails to validate against control chars in header names which may lead to HTTP request smuggling

netty

Vendor fix available · Affected: netty · Exploitation: possible (1 to 10%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

2.9%probability of exploitation in the next 30 days

87th percentile

050100

Higher than 87% of scored CVEs

6.5MediumCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

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.

Affected products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

netty · netty<= 4.1.7.0.Final

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Possible (1 to 10%). EPSS between 1% and 10%.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Inconsistent Interpretation of HTTP Requests · Injection and Smuggling
Vendor: netty
Published: December 2021
Band: Possible (1 to 10%), December 2021

CoverageNo articles yet

No CyberSIXT article names CVE-2021-43797 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.