Secuno
ENNL
Book demo

CVE-2026-55833

Netty denial of service

7.5 HIGHPublic exploitEPSS 0.66%
  1. Published20 Jul 2026

Description

Netty is a network application framework for development of protocol servers and clients. Prior to 4.1.136.Final and 4.2.16.Final, Netty SPDY header decoding continues inflating zlib-compressed header blocks after the raw header parser has exceeded `maxHeaderSize` and marked the frame truncated in `SpdyFrameCodec`, allowing a remote peer to send a small compressed `HEADERS` block that expands into much larger raw header data and causes compression-amplified CPU and allocation churn. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

CVSS 3.1 breakdown

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

Affected products

Netty≥ 4.1.0 < 4.1.136 · ≥ 4.2.0 < 4.2.16

Remediation

Fixed in
Netty≥ 4.1.136

References

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

CVE-2026-904418.1
A missing authorization vulnerability in the wgagent management daemon's session…
CVE-2026-866088.2
The WP Recipe Maker WordPress plugin before 10.8.2 does not have any authorisation…
CVE-2026-143218.2
The divi-dash WordPress plugin before 1.0.7 does not validate the source of the client…
CVE-2026-336258.8
LMDeploy is a toolkit for compressing, deploying, and serving large language models.…
CVE-2026-834658.2
Vulnerability in the Oracle Mobile Application Server product of Oracle E-Business…
CVE-2026-834578.1
Vulnerability in the Oracle Demand Signal Repository product of Oracle E-Business Suite…

Frequently asked

Is CVE-2026-55833 being actively exploited?

CVE-2026-55833 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.66%.

How severe is CVE-2026-55833?

CVE-2026-55833 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.66% probability of exploitation.

Which products are affected by CVE-2026-55833?

Affected products include Netty.

How do I fix CVE-2026-55833?

Upgrade affected software to a fixed version, for example Netty 4.1.136 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-55833 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.

See how prioritisation worksBook a demo

Get Patch this first every Monday

Five vulnerabilities that matter this week, ranked on real exploitation. Plain language, one email, no spam.

You can unsubscribe with one click from every issue. We handle your details as described in our privacy policy.

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