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NVD / CVE Program· CNA mitre

CVE-2020-11612: The ZlibDecoders in Netty 4.1.x before 4.1.46 allow for unbounded memory allocation while decoding a ZlibEncoded byte stream.

HighCVSS 7.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 33/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 9.1% (FIRST EPSS); higher than 95.3% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: netty (Debian:10) 1:4.1.33-1+deb10u2; netty (Debian:12) 1:4.1.48-1; netty (Debian:9) 1:4.1.7-2+deb9u2.
  • Mentioned 5 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to netty (Debian:10) 1:4.1.33-1+deb10u2; netty (Debian:12) 1:4.1.48-1; netty (Debian:9) 1:4.1.7-2+deb9u2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

The ZlibDecoders in Netty 4.1.x before 4.1.46 allow for unbounded memory allocation while decoding a ZlibEncoded byte stream. An attacker could send a large ZlibEncoded byte stream to the Netty server, forcing the server to allocate all of its free memory to a single decoder.

Published
Apr 7, 2020
Updated
Jun 16, 2026
EPSS
9.1% · 95th percentile

Report tools

JSON

Action score

33

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
3 / 30 · 9.1%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
nettynetty
debiandebian linux
fedoraprojectfedora
netapponcommand api services
netapponcommand insight
netapponcommand workflow automation
oraclecommunications brm - elastic charging engine
oraclecommunications cloud native core service communication proxy
oraclecommunications design studio
oraclenosql database
oraclesiebel core - server framework
oraclewebcenter portal

and 1 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • debian debian linux10.0
  • debian debian linux9.0
  • fedoraproject fedora33
  • netapp oncommand api servicesall versions
  • netapp oncommand insightall versions
  • netapp oncommand workflow automationall versions
  • netty netty4.1 and later · before 4.1.46
  • oracle communications brm - elastic charging engine12.0.0.3
  • oracle communications cloud native core service communication proxy1.5.2
  • oracle communications design studio7.4.2
  • oracle communications messaging server8.1
  • oracle nosql databasebefore 20.3
  • oracle siebel core - server frameworkbefore 21.5
  • oracle webcenter portal12.2.1.3.0
  • oracle webcenter portal12.2.1.4.0

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:10nettybefore 1:4.1.33-1+deb10u21:4.1.33-1+deb10u2
Debian:12nettybefore 1:4.1.48-11:4.1.48-1
Debian:9nettybefore 1:4.1.7-2+deb9u21:4.1.7-2+deb9u2
Mavenio.netty:netty-handlerfrom 4.1.0 · before 4.1.464.1.46
openSUSE:Tumbleweednettybefore 4.1.60-1.44.1.60-1.4
Red Hat:a_mq_clients:2::el6python-qpid-protonbefore 0:0.31.0-3.el6_100:0.31.0-3.el6_10
Red Hat:a_mq_clients:2::el6python-qpid-proton-docsbefore 0:0.31.0-3.el6_100:0.31.0-3.el6_10
Red Hat:a_mq_clients:2::el6qpid-cppbefore 0:1.36.0-30.el6_10amq0:1.36.0-30.el6_10amq
Red Hat:a_mq_clients:2::el6qpid-cpp-clientbefore 0:1.36.0-30.el6_10amq0:1.36.0-30.el6_10amq
Red Hat:a_mq_clients:2::el6qpid-cpp-client-develbefore 0:1.36.0-30.el6_10amq0:1.36.0-30.el6_10amq
Red Hat:a_mq_clients:2::el6qpid-cpp-client-docsbefore 0:1.36.0-30.el6_10amq0:1.36.0-30.el6_10amq
Red Hat:a_mq_clients:2::el6qpid-cpp-debuginfobefore 0:1.36.0-30.el6_10amq0:1.36.0-30.el6_10amq
Red Hat:a_mq_clients:2::el6qpid-protonbefore 0:0.31.0-3.el6_100:0.31.0-3.el6_10
Red Hat:a_mq_clients:2::el6qpid-proton-cbefore 0:0.31.0-3.el6_100:0.31.0-3.el6_10
Red Hat:a_mq_clients:2::el6qpid-proton-c-develbefore 0:0.31.0-3.el6_100:0.31.0-3.el6_10
Red Hat:a_mq_clients:2::el6qpid-proton-c-docsbefore 0:0.31.0-3.el6_100:0.31.0-3.el6_10
Red Hat:a_mq_clients:2::el6qpid-proton-cppbefore 0:0.31.0-3.el6_100:0.31.0-3.el6_10
Red Hat:a_mq_clients:2::el6qpid-proton-cpp-develbefore 0:0.31.0-3.el6_100:0.31.0-3.el6_10
Red Hat:a_mq_clients:2::el6qpid-proton-cpp-docsbefore 0:0.31.0-3.el6_100:0.31.0-3.el6_10
Red Hat:a_mq_clients:2::el6qpid-proton-debuginfobefore 0:0.31.0-3.el6_100:0.31.0-3.el6_10
Red Hat:a_mq_clients:2::el6qpid-proton-testsbefore 0:0.31.0-3.el6_100:0.31.0-3.el6_10
Red Hat:a_mq_clients:2::el7python-qpid-protonbefore 0:0.31.0-3.el70:0.31.0-3.el7
Red Hat:a_mq_clients:2::el7python-qpid-proton-docsbefore 0:0.31.0-3.el70:0.31.0-3.el7
Red Hat:a_mq_clients:2::el7qpid-cppbefore 0:1.36.0-30.el7amq0:1.36.0-30.el7amq

+96

Same product

netty: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-47691Netty has Insufficient Bailiwick Validation for NS Records
    40Plan
  • CVE-2026-45674Netty Vulnerable to DNS Cache Poisoning via Missing Bailiwick Checks in CNAME Records
    40Plan
  • CVE-2019-20445HttpObjectDecoder.java in Netty before 4.1.44 allows a Content-Length header to be accompanied by a second Content-Length header, or by a…
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2020-7238Jan 27, 2020 · Netty 4.1.43.Final allows HTTP Request Smuggling because it mishandles Transfer-Encoding whitespace (such as a…
    31Monitor
  • ← EarlierCVE-2019-20444Jan 29, 2020 · HttpObjectDecoder.java in Netty before 4.1.44 allows an HTTP header that lacks a colon, which might be interpreted as a separate header…
    39Monitor
  • Later →CVE-2021-21290Feb 8, 2021 · Local Information Disclosure Vulnerability in Netty on Unix-Like systems due temporary files
    23Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:netty1:4.1.48-1 · Debian:12Package registry (OSV)
Maven:io.netty:netty-handler4.1.46Package registry (OSV)
opensuse:netty4.1.60-1.4 · openSUSE:TumbleweedPackage registry (OSV)
red hat:python-qpid-proton0:0.31.0-3.el6_10 · Red Hat:a_mq_clients:2::el6Package registry (OSV)
red hat:python-qpid-proton-docs0:0.31.0-3.el6_10 · Red Hat:a_mq_clients:2::el6Package registry (OSV)
red hat:qpid-cpp0:1.36.0-30.el6_10amq · Red Hat:a_mq_clients:2::el6Package registry (OSV)
red hat:qpid-cpp-client0:1.36.0-30.el6_10amq · Red Hat:a_mq_clients:2::el6Package registry (OSV)
red hat:qpid-cpp-client-devel0:1.36.0-30.el6_10amq · Red Hat:a_mq_clients:2::el6Package registry (OSV)
red hat:qpid-cpp-client-docs0:1.36.0-30.el6_10amq · Red Hat:a_mq_clients:2::el6Package registry (OSV)
red hat:qpid-cpp-debuginfo0:1.36.0-30.el6_10amq · Red Hat:a_mq_clients:2::el6Package registry (OSV)
red hat:qpid-proton0:0.31.0-3.el6_10 · Red Hat:a_mq_clients:2::el6Package registry (OSV)
red hat:qpid-proton-c0:0.31.0-3.el6_10 · Red Hat:a_mq_clients:2::el6Package registry (OSV)
red hat:qpid-proton-c-devel0:0.31.0-3.el6_10 · Red Hat:a_mq_clients:2::el6Package registry (OSV)
red hat:qpid-proton-c-docs0:0.31.0-3.el6_10 · Red Hat:a_mq_clients:2::el6Package registry (OSV)
red hat:qpid-proton-cpp0:0.31.0-3.el6_10 · Red Hat:a_mq_clients:2::el6Package registry (OSV)
suse:netty4.1.44.Final-150300.4.3.2 · SUSE:Manager Server Module 4.2Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-770 · Allocation of Resources Without Limits or Throttling

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (19 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records