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CVE-2026-33870

Netty vulnerability

7.5 HIGHPublic exploitEPSS 0.70%
  1. Published27 Mar 2026

Description

Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, Netty incorrectly parses quoted strings in HTTP/1.1 chunked transfer encoding extension values, enabling request smuggling attacks. Versions 4.1.132.Final and 4.2.10.Final fix the issue.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityNone
IntegrityHigh
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected products

Netty≥ 4.2.0 < 4.2.10 · < 4.1.132

Remediation

Fixed in
Netty≥ 4.2.10

References

and 14 more references

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Frequently asked

Is CVE-2026-33870 being actively exploited?

CVE-2026-33870 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.70%.

How severe is CVE-2026-33870?

CVE-2026-33870 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.70% probability of exploitation.

Which products are affected by CVE-2026-33870?

Affected products include Netty.

How do I fix CVE-2026-33870?

Upgrade affected software to a fixed version, for example Netty 4.2.10 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-33870 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.