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HIGH severity

GHSA-9vjp-v76f-g363 — netty-codec

HIGHFix: netty/netty@6da4956

GHSA-9vjp-v76f-g363 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in io.netty:netty-codec. A fix is available for io.netty:netty-codec — see the affected versions and patch details below.

SnappyFrameDecoder doesn't restrict chunk length any may buffer skippable chunks in an unnecessary way

Also known asCVE-2021-37137
Published
Sep 9, 2021
Updated
Jul 8, 2026
Affected
3 pkgs
Patched
1 / 3
Exploits
None indexed
Exploitation data as of Sep 24, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
6.7%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs94th percentile — riskier than 94% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

GHSA-9vjp-v76f-g363 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

3 pkgs affected
☕io.netty:netty-codec☕org.jboss.netty:netty☕io.netty:netty

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

Impact

The Snappy frame decoder function doesn't restrict the chunk length which may lead to excessive memory usage. Beside this it also may buffer reserved skippable chunks until the whole chunk was received which may lead to excessive memory usage as well.

This vulnerability can be triggered by supplying malicious input that decompresses to a very big size (via a network stream or a file) or by sending a huge skippable chunk.

Impact

All users of SnappyFrameDecoder are affected and so the application may be in risk for a DoS attach due excessive memory usage.

References

https://github.com/netty/netty/blob/netty-4.1.67.Final/codec/src/main/java/io/netty/handler/codec/compression/SnappyFrameDecoder.java#L79 https://github.com/netty/netty/blob/netty-4.1.67.Final/codec/src/main/java/io/netty/handler/codec/compression/SnappyFrameDecoder.java#L171 https://github.com/netty/netty/blob/netty-4.1.67.Final/codec/src/main/java/io/netty/handler/codec/compression/SnappyFrameDecoder.java#L185

Affected Packages

3 total 1 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenio.netty:netty-codec≥ 4.0.0&&< 4.1.68.Final4.1.68.Finalio.netty:netty-codec:4.1.68.Final
☕Mavenorg.jboss.netty:nettyall versionsNo fix
☕Mavenio.netty:nettyall versionsNo fix

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.netty:netty-codec, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update io.netty:netty-codec to 4.1.68.Final or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9vjp-v76f-g363 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-9vjp-v76f-g363 can be triaged on real exposure rather than presence alone.

Tailored to GHSA-9vjp-v76f-g363. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

In OpenShift Container Platform (OCP), the Hive/Presto/Hadoop components that comprise the OCP Metering stack, ship the vulnerable version of netty-codec package. Since the release of OCP 4.6, the Metering product has been deprecated [1], hence the affected components are marked as wontfix. This may be fixed in the…

ProductFixed inAdvisory
Logging subsystem for Red Hat OpenShift 5.4openshift-logging/elasticsearch6-rhel8:v6.8.1-156RHSA-2022:2216
OpenShift Logging 5.1openshift-logging/elasticsearch6-rhel8:v6.8.1-67RHSA-2021:5128
OpenShift Logging 5.2openshift-logging/elasticsearch6-rhel8:v6.8.1-66RHSA-2021:5127
OpenShift Logging 5.2openshift-logging/elasticsearch6-rhel8:v6.8.1-157RHSA-2022:2218
OpenShift Logging 5.3openshift-logging/elasticsearch6-rhel8:v6.8.1-65RHSA-2021:5129
OpenShift Logging 5.3openshift-logging/elasticsearch6-rhel8:v6.8.1-159RHSA-2022:2217
Red Hat AMQ 7.9.1netty-codecRHSA-2021:4851
Red Hat AMQ Streams 2.0.0netty-codecRHSA-2022:0138

Frequently Asked Questions

### Impact The Snappy frame decoder function doesn't restrict the chunk length which may lead to excessive memory usage. Beside this it also may buffer reserved skippable chunks until the whole chunk was received which may lead to excessive memory usage as well. This vulnerability can be triggered by supplying malicious input that decompresses to a very big size (via a network stream or a file) or by sending a huge skippable chunk. ### Impact All users of SnappyFrameDecoder are affected and so the application may be in risk for a DoS attach due excessive memory usage. ### References https:
O3 Security · Impact-Aware SCA

Is GHSA-9vjp-v76f-g363 in your dependencies?

O3 Security finds GHSA-9vjp-v76f-g363 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-9vjp-v76f-g363: netty-codec (High 7.5) | O3 Security