CVE-2020-11612

CVE-2020-11612 is a high-severity vulnerability in Netty with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-770.

Key facts

• Severity: High (CVSS 3.x base score 7.5)
• CVSS v2: 5.0
• EPSS exploit prediction: 9% (95th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-770
• Affected product: Netty
• Published: 2020-04-07
• Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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. 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.

How severe is CVE-2020-11612?

CVE-2020-11612 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2020-11612 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 9% (95th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-11612?

CVE-2020-11612 primarily affects Netty. In total, 15 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-11612?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2020-11612 published?

CVE-2020-11612 was published on 2020-04-07 and last updated on 2026-06-17.

References

• https://github.com/netty/netty/compare/netty-4.1.45.Final...netty-4.1.46.Final
• https://github.com/netty/netty/issues/6168
• https://github.com/netty/netty/pull/9924
• https://lists.apache.org/thread.html/r14446ed58208cb6d97b6faa6ebf145f1cf2c70c0886c0c133f4d3b6f%40%3Ccommits.druid.apache.org%3E
• https://lists.apache.org/thread.html/r255ed239e65d0596812362adc474bee96caf7ba042c7ad2f3c62cec7%40%3Cissues.zookeeper.apache.org%3E
• https://lists.apache.org/thread.html/r281882fdf9ea89aac02fd2f92786693a956aac2ce9840cce87c7df6b%40%3Ccommits.zookeeper.apache.org%3E
• https://lists.apache.org/thread.html/r2958e4d49ee046e1e561e44fdc114a0d2285927501880f15852a9b53%40%3Ccommits.druid.apache.org%3E
• https://lists.apache.org/thread.html/r31424427cc6d7db46beac481bdeed9a823fc20bb1b9deede38557f71%40%3Cnotifications.zookeeper.apache.org%3E
• https://lists.apache.org/thread.html/r3195127e46c87a680b5d1d3733470f83b886bfd3b890c50df718bed1%40%3Ccommits.druid.apache.org%3E
• https://lists.apache.org/thread.html/r3ea4918d20d0c1fa26cac74cc7cda001d8990bc43473d062867ef70d%40%3Cnotifications.zookeeper.apache.org%3E
• https://lists.apache.org/thread.html/r4a7e4e23bd84ac24abf30ab5d5edf989c02b555e1eca6a2f28636692%40%3Cnotifications.zookeeper.apache.org%3E
• https://lists.apache.org/thread.html/r4f4a14d6a608db447b725ec2e96c26ac9664d83cd879aa21e2cfeb24%40%3Cnotifications.zookeeper.apache.org%3E
• https://lists.apache.org/thread.html/r5030cd8ea5df1e64cf6a7b633eff145992fbca03e8bfc687cd2427ab%40%3Cnotifications.zookeeper.apache.org%3E
• https://lists.apache.org/thread.html/r5a0b1f0b1c3bcd66f5177fbd6f6de2d0f8cae24a13ab2669f274251a%40%3Cnotifications.zookeeper.apache.org%3E
• https://lists.apache.org/thread.html/r5b1ad61552591b747cd31b3a908d5ff2e8f2a8a6847583dd6b7b1ee7%40%3Cissues.zookeeper.apache.org%3E
• https://lists.apache.org/thread.html/r69b23a94d4ae45394cabae012dd1f4a963996869c44c478eb1c61082%40%3Ccommits.zookeeper.apache.org%3E
• https://lists.apache.org/thread.html/r7641ee788e1eb1be4bb206a7d15f8a64ec6ef23e5ec6132d5a567695%40%3Cnotifications.zookeeper.apache.org%3E
• https://lists.apache.org/thread.html/r7790b9d99696d9eddce8a8c96f13bb68460984294ea6fea3800143e4%40%3Ccommits.pulsar.apache.org%3E
• https://lists.apache.org/thread.html/r7836bbdbe95c99d4d725199f0c169927d4e87ba57e4beeeb699c097a%40%3Ccommits.druid.apache.org%3E
• https://lists.apache.org/thread.html/r832724df393a7ef25ca4c7c2eb83ad2d6c21c74569acda5233f9f1ec%40%3Ccommits.pulsar.apache.org%3E
• https://lists.apache.org/thread.html/r866288c2ada00ce148b7307cdf869f15f24302b3eb2128af33830997%40%3Ccommits.zookeeper.apache.org%3E
• https://lists.apache.org/thread.html/r88e2b91560c065ed67e62adf8f401c417e4d70256d11ea447215a70c%40%3Cissues.zookeeper.apache.org%3E
• https://lists.apache.org/thread.html/r8a654f11e1172b0effbfd6f8d5b6ca651ae4ac724a976923c268a42f%40%3Ccommits.druid.apache.org%3E
• https://lists.apache.org/thread.html/r9addb580456807cd11d6f0c6b6373b7d7161d06d2278866c30c7febb%40%3Ccommits.zookeeper.apache.org%3E
• https://lists.apache.org/thread.html/r9c30b7fca4baedebcb46d6e0f90071b30cc4a0e074164d50122ec5ec%40%3Ccommits.zookeeper.apache.org%3E
• https://lists.apache.org/thread.html/ra98e3a8541a09271f96478d5e22c7e3bd1afdf48641c8be25d62d9f9%40%3Ccommits.druid.apache.org%3E
• https://lists.apache.org/thread.html/raaac04b7567c554786132144bea3dcb72568edd410c1e6f0101742e7%40%3Cissues.flink.apache.org%3E
• https://lists.apache.org/thread.html/rd302ddb501fa02c5119120e5fc21df9a1c00e221c490edbe2d7ad365%40%3Cnotifications.zookeeper.apache.org%3E
• https://lists.apache.org/thread.html/rdb69125652311d0c41f6066ff44072a3642cf33a4b5e3c4f9c1ec9c2%40%3Ccommits.pulsar.apache.org%3E
• https://lists.apache.org/thread.html/re1ea144e91f03175d661b2d3e97c7d74b912e019613fa90419cf63f4%40%3Cissues.zookeeper.apache.org%3E

Affected products (15)

• cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*
• cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
• cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
• cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
• cpe:2.3:a:netapp:oncommand_api_services:-:*:*:*:*:*:*:*
• cpe:2.3:a:netapp:oncommand_insight:-:*:*:*:*:*:*:*
• cpe:2.3:a:netapp:oncommand_workflow_automation:-:*:*:*:*:*:*:*
• cpe:2.3:a:oracle:communications_brm_-_elastic_charging_engine:12.0.0.3:*:*:*:*:*:*:*
• cpe:2.3:a:oracle:communications_cloud_native_core_service_communication_proxy:1.5.2:*:*:*:*:*:*:*
• cpe:2.3:a:oracle:communications_design_studio:7.4.2:*:*:*:*:*:*:*
• cpe:2.3:a:oracle:nosql_database:*:*:*:*:*:*:*:*
• cpe:2.3:a:oracle:siebel_core_-_server_framework:*:*:*:*:*:*:*:*
• cpe:2.3:a:oracle:webcenter_portal:12.2.1.3.0:*:*:*:*:*:*:*
• cpe:2.3:a:oracle:webcenter_portal:12.2.1.4.0:*:*:*:*:*:*:*
• cpe:2.3:o:oracle:communications_messaging_server:8.1:*:*:*:*:*:*:*

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