CVE-2021-21290

Local Information Disclosure Vulnerability in Netty on Unix-Like systems due temporary files

Published Feb 8, 2021 CVSS 3.1 · 6.2 Medium EPSS 1.8% KEV · Not listed
Description
Netty is an open-source, asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. In Netty before version 4.1.59.Final there is a vulnerability on Unix-like systems involving an insecure temp file. When netty's multipart decoders are used local information disclosure can occur via the local system temporary directory if temporary storing uploads on the disk is enabled. On unix-like systems, the temporary directory is shared between all user. As such, writing to this directory using APIs that do not explicitly set the file/directory permissions can lead to information disclosure. Of note, this does not impact modern MacOS Operating Systems. The method "File.createTempFile" on unix-like systems creates a random file, but, by default will create this file with the permissions "-rw-r--r--". Thus, if sensitive information is written to this file, other local users can read this information. This is the case in netty's "AbstractDiskHttpData" is vulnerable. This has been fixed in version 4.1.59.Final. As a workaround, one may specify your own "java.io.tmpdir" when you start the JVM or use "DefaultHttpDataFactory.setBaseDir(...)" to set the directory to something that is only readable by the current user.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-2555-1 netty security update
Debian DSA Debian DSA DSA-4885-1 netty security update
EUVD EUVD EUVD-2021-0535 Netty is an open-source, asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. In Netty before version 4.1.59.Final there is a vulnerability on Unix-like systems involving an insecure temp file. When netty's multipart decoders are used local information disclosure can occur via the local system temporary directory if temporary storing uploads on the disk is enabled. On unix-like systems, the temporary directory is shared between all user. As such, writing to this directory using APIs that do not explicitly set the file/directory permissions can lead to information disclosure. Of note, this does not impact modern MacOS Operating Systems. The method "File.createTempFile" on unix-like systems creates a random file, but, by default will create this file with the permissions "-rw-r--r--". Thus, if sensitive information is written to this file, other local users can read this information. This is the case in netty's "AbstractDiskHttpData" is vulnerable. This has been fixed in version 4.1.59.Final. As a workaround, one may specify your own "java.io.tmpdir" when you start the JVM or use "DefaultHttpDataFactory.setBaseDir(...)" to set the directory to something that is only readable by the current user.
Github GHSA Github GHSA GHSA-5mcr-gq6c-3hq2 Local Information Disclosure Vulnerability in Netty on Unix-Like systems
Ubuntu USN Ubuntu USN USN-6049-1 Netty vulnerabilities
References
Link Providers
https://github.com/netty/netty/commit/c735357bf29d07856ad171c6611a2e1a0e0000ec cve-icon cve-icon
https://github.com/netty/netty/security/advisories/GHSA-5mcr-gq6c-3hq2 cve-icon cve-icon
https://lists.apache.org/thread.html/r0053443ce19ff125981559f8c51cf66e3ab4350f47812b8cf0733a05%40%3Cdev.kafka.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r02e467123d45006a1dda20a38349e9c74c3a4b53e2e07be0939ecb3f%40%3Cdev.ranger.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r0857b613604c696bf9743f0af047360baaded48b1c75cf6945a083c5%40%3Cjira.kafka.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r10308b625e49d4e9491d7e079606ca0df2f0a4d828f1ad1da64ba47b%40%3Cjira.kafka.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r1908a34b9cc7120e5c19968a116ddbcffea5e9deb76c2be4fa461904%40%3Cdev.zookeeper.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r2748097ea4b774292539cf3de6e3b267fc7a88d6c8ec40f4e2e87bd4%40%3Cdev.kafka.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r2936730ef0a06e724b96539bc7eacfcd3628987c16b1b99c790e7b87%40%3Cissues.zookeeper.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r2fda4dab73097051977f2ab818f75e04fbcb15bb1003c8530eac1059%40%3Cjira.kafka.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r326ec431f06eab7cb7113a7a338e59731b8d556d05258457f12bac1b%40%3Cdev.kafka.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r4efed2c501681cb2e8d629da16e48d9eac429624fd4c9a8c6b8e7020%40%3Cdev.tinkerpop.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r584cf871f188c406d8bd447ff4e2fd9817fca862436c064d0951a071%40%3Ccommits.pulsar.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r59bac5c09f7a4179b9e2460e8f41c278aaf3b9a21cc23678eb893e41%40%3Cjira.kafka.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r5bf303d7c04da78f276765da08559fdc62420f1df539b277ca31f63b%40%3Cissues.zookeeper.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r5c701840aa2845191721e39821445e1e8c59711e71942b7796a6ec29%40%3Cusers.activemq.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r5e4a540089760c8ecc2c411309d74264f1dad634ad93ad583ca16214%40%3Ccommits.kafka.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r5e66e286afb5506cdfe9bbf68a323e8d09614f6d1ddc806ed0224700%40%3Cjira.kafka.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r71dbb66747ff537640bb91eb0b2b24edef21ac07728097016f58b01f%40%3Ccommits.kafka.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r743149dcc8db1de473e6bff0b3ddf10140a7357bc2add75f7d1fbb12%40%3Cdev.zookeeper.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r790c2926efcd062067eb18fde2486527596d7275381cfaff2f7b3890%40%3Cissues.bookkeeper.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r7bb3cdc192e9a6f863d3ea05422f09fa1ae2b88d4663e63696ee7ef5%40%3Cdev.ranger.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/r9924ef9357537722b28d04c98a189750b80694a19754e5057c34ca48%40%3Ccommits.pulsar.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/ra0fc2b4553dd7aaf75febb61052b7f1243ac3a180a71c01f29093013%40%3Cjira.kafka.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/ra503756ced78fdc2136bd33e87cb7553028645b261b1f5c6186a121e%40%3Cjira.kafka.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/rb06c1e766aa45ee422e8261a8249b561784186483e8f742ea627bda4%40%3Cdev.kafka.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/rb51d6202ff1a773f96eaa694b7da4ad3f44922c40b3d4e1a19c2f325%40%3Ccommits.pulsar.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/rb592033a2462548d061a83ac9449c5ff66098751748fcd1e2d008233%40%3Cissues.zookeeper.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/rc0087125cb15b4b78e44000f841cd37fefedfda942fd7ddf3ad1b528%40%3Cissues.zookeeper.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/rc488f80094872ad925f0c73d283d4c00d32def81977438e27a3dc2bb%40%3Cjira.kafka.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/rcd163e421273e8dca1c71ea298dce3dd11b41d51c3a812e0394e6a5d%40%3Ccommits.pulsar.apache.org%3E cve-icon cve-icon
https://lists.apache.org/thread.html/rdba4f78ac55f803893a1a2265181595e79e3aa027e2e651dfba98c18%40%3Cjira.kafka.apache.org%3E cve-icon cve-icon
https://lists.debian.org/debian-lts-announce/2021/02/msg00016.html cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2021-21290 cve-icon
https://security.netapp.com/advisory/ntap-20220210-0011/ cve-icon cve-icon
https://www.cve.org/CVERecord?id=CVE-2021-21290 cve-icon
https://www.debian.org/security/2021/dsa-4885 cve-icon cve-icon
https://www.oracle.com//security-alerts/cpujul2021.html cve-icon cve-icon
https://www.oracle.com/security-alerts/cpuApr2021.html cve-icon cve-icon
https://www.oracle.com/security-alerts/cpuapr2022.html cve-icon cve-icon
https://www.oracle.com/security-alerts/cpuoct2021.html cve-icon cve-icon
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Oct 8, 2026, 9:14 PM
Reserved
Dec 22, 2020, 12:00 AM
Status
Modified
Published
Feb 8, 2021, 8:15 PM
Modified
Oct 8, 2026, 10:17 PM
Severity
Moderate
Public date
Feb 9, 2021, 12:00 AM