CVE-2021-21290: Local Information Disclosure Vulnerability in Netty on Unix-Like systems due temporary files
Noroxi assessment
Priority: Monitor (action score 23/100)
- 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: 1.7% (FIRST EPSS); higher than 78.7% of all records.
- Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: netty netty 4.1.59.Final.
- Mentioned 4 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to netty netty 4.1.59.Final 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
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.
- Published
- Feb 8, 2021
- Updated
- Oct 8, 2026
- EPSS
- 1.7% · 78th percentile
- CWE
- CWE-378
Report tools
Action score
23
Low priority for now.
- CVSS
- 22 / 40 · 5.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 1.7%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 5.5
- CNA · GitHub_M
- 6.2
- 0.7 point gap
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
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
If any of these changes, we'll tell you in the daily email digest.
Is your version affected? Check itNoroxi 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.
We use this product, ask for helpAffected 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.
| Vendor | Product | CPE |
|---|---|---|
| netty | netty | cpe:2.3:a:netty:netty |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| quarkus | quarkus | cpe:2.3:a:quarkus:quarkus |
| oracle | banking corporate lending process management | cpe:2.3:a:oracle:banking_corporate_lending_process_management |
| oracle | banking credit facilities process management | cpe:2.3:a:oracle:banking_credit_facilities_process_management |
| oracle | banking trade finance process management | cpe:2.3:a:oracle:banking_trade_finance_process_management |
| oracle | communications brm - elastic charging engine | cpe:2.3:a:oracle:communications_brm_-_elastic_charging_engine |
| oracle | communications design studio | cpe:2.3:a:oracle:communications_design_studio |
| oracle | communications messaging server | cpe:2.3:a:oracle:communications_messaging_server |
| oracle | nosql database | cpe:2.3:a:oracle:nosql_database |
| netapp | active iq unified manager | cpe:2.3:a:netapp:active_iq_unified_manager |
| netapp | cloud secure agent | cpe:2.3:a:netapp:cloud_secure_agent |
and 1 more
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
netty netty
- < 4.1.59.Finalaffected
Affected versions · NVD (20)
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
- netapp active iq unified managerall versions
- netapp cloud secure agentall versions
- netapp snapcenterall versions
- netty nettybefore 4.1.59
- oracle banking corporate lending process management14.2.0
- oracle banking corporate lending process management14.3.0
- oracle banking corporate lending process management14.5.0
- oracle banking credit facilities process management14.2.0
- oracle banking credit facilities process management14.3.0
- oracle banking credit facilities process management14.5.0
- oracle banking trade finance process management14.2.0
- oracle banking trade finance process management14.3.0
- oracle banking trade finance process management14.5.0
- oracle communications brm - elastic charging engine12.0.0.3
- oracle communications design studio7.4.2
- oracle communications messaging server8.1
- oracle nosql databasebefore 20.3
- quarkus quarkusup to 1.13.7 inclusive
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:10 | netty | before 1:4.1.33-1+deb10u2 | 1:4.1.33-1+deb10u2 |
| Debian:12 | netty | before 1:4.1.48-2 | 1:4.1.48-2 |
| Debian:9 | netty | before 1:4.1.7-2+deb9u3 | 1:4.1.7-2+deb9u3 |
| Maven | io.netty:netty | from 0 | — |
| Maven | io.netty:netty-codec-http | from 4.0.0 · before 4.1.59.Final | 4.1.59.Final |
| Maven | org.jboss.netty:netty | from 0 | — |
| openSUSE:Leap 15.3 | netty | before 4.1.75-150200.4.6.2 | 4.1.75-150200.4.6.2 |
| openSUSE:Tumbleweed | netty | before 4.1.60-1.4 | 4.1.60-1.4 |
| Red Hat:a_mq_clients:2::el7 | python-qpid-proton | before 0:0.33.0-6.el7_9 | 0:0.33.0-6.el7_9 |
| Red Hat:a_mq_clients:2::el7 | python-qpid-proton-docs | before 0:0.33.0-6.el7_9 | 0:0.33.0-6.el7_9 |
| Red Hat:a_mq_clients:2::el7 | qpid-proton | before 0:0.33.0-6.el7_9 | 0:0.33.0-6.el7_9 |
| Red Hat:a_mq_clients:2::el7 | qpid-proton-c | before 0:0.33.0-6.el7_9 | 0:0.33.0-6.el7_9 |
| Red Hat:a_mq_clients:2::el7 | qpid-proton-c-devel | before 0:0.33.0-6.el7_9 | 0:0.33.0-6.el7_9 |
| Red Hat:a_mq_clients:2::el7 | qpid-proton-c-docs | before 0:0.33.0-6.el7_9 | 0:0.33.0-6.el7_9 |
| Red Hat:a_mq_clients:2::el7 | qpid-proton-cpp | before 0:0.33.0-6.el7_9 | 0:0.33.0-6.el7_9 |
| Red Hat:a_mq_clients:2::el7 | qpid-proton-cpp-devel | before 0:0.33.0-6.el7_9 | 0:0.33.0-6.el7_9 |
| Red Hat:a_mq_clients:2::el7 | qpid-proton-cpp-docs | before 0:0.33.0-6.el7_9 | 0:0.33.0-6.el7_9 |
| Red Hat:a_mq_clients:2::el7 | qpid-proton-debuginfo | before 0:0.33.0-6.el7_9 | 0:0.33.0-6.el7_9 |
| Red Hat:a_mq_clients:2::el7 | qpid-proton-tests | before 0:0.33.0-6.el7_9 | 0:0.33.0-6.el7_9 |
| Red Hat:a_mq_clients:2::el7 | rubygem-qpid_proton | before 0:0.33.0-6.el7_9 | 0:0.33.0-6.el7_9 |
| Red Hat:a_mq_clients:2::el8 | python-qpid-proton-docs | before 0:0.33.0-8.el8 | 0:0.33.0-8.el8 |
| Red Hat:a_mq_clients:2::el8 | python3-qpid-proton | before 0:0.33.0-8.el8 | 0:0.33.0-8.el8 |
| Red Hat:a_mq_clients:2::el8 | python3-qpid-proton-debuginfo | before 0:0.33.0-8.el8 | 0:0.33.0-8.el8 |
| Red Hat:a_mq_clients:2::el8 | qpid-proton | before 0:0.33.0-8.el8 | 0:0.33.0-8.el8 |
+96
Same product
netty: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-47691Netty has Insufficient Bailiwick Validation for NS Records40Plan
- CVE-2026-45674Netty Vulnerable to DNS Cache Poisoning via Missing Bailiwick Checks in CNAME Records40Plan
- 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-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
- ← EarlierCVE-2020-11612Apr 7, 2020 · The ZlibDecoders in Netty 4.1.x before 4.1.46 allow for unbounded memory allocation while decoding a ZlibEncoded byte stream.33Monitor
- Later →CVE-2021-21295Mar 9, 2021 · Possible request smuggling in HTTP/2 due missing validation29Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| netty netty | 4.1.59.Final · description | Vendor (CNA) |
| debian:netty | 1:4.1.48-2 · Debian:12 | Package registry (OSV) |
| Maven:io.netty:netty-codec-http | 4.1.59.Final | Package registry (OSV) |
| opensuse:netty | 4.1.75-150200.4.6.2 · openSUSE:Leap 15.3 | Package registry (OSV) |
| red hat:python-qpid-proton | 0:0.33.0-6.el7_9 · Red Hat:a_mq_clients:2::el7 | Package registry (OSV) |
| red hat:python-qpid-proton-docs | 0:0.33.0-6.el7_9 · Red Hat:a_mq_clients:2::el7 | Package registry (OSV) |
| red hat:qpid-proton | 0:0.33.0-6.el7_9 · Red Hat:a_mq_clients:2::el7 | Package registry (OSV) |
| red hat:qpid-proton-c | 0:0.33.0-6.el7_9 · Red Hat:a_mq_clients:2::el7 | Package registry (OSV) |
| red hat:qpid-proton-c-devel | 0:0.33.0-6.el7_9 · Red Hat:a_mq_clients:2::el7 | Package registry (OSV) |
| red hat:qpid-proton-c-docs | 0:0.33.0-6.el7_9 · Red Hat:a_mq_clients:2::el7 | Package registry (OSV) |
| red hat:qpid-proton-cpp | 0:0.33.0-6.el7_9 · Red Hat:a_mq_clients:2::el7 | Package registry (OSV) |
| red hat:qpid-proton-cpp-devel | 0:0.33.0-6.el7_9 · Red Hat:a_mq_clients:2::el7 | Package registry (OSV) |
| red hat:qpid-proton-cpp-docs | 0:0.33.0-6.el7_9 · Red Hat:a_mq_clients:2::el7 | Package registry (OSV) |
| red hat:qpid-proton-debuginfo | 0:0.33.0-6.el7_9 · Red Hat:a_mq_clients:2::el7 | Package registry (OSV) |
| red hat:qpid-proton-tests | 0:0.33.0-6.el7_9 · Red Hat:a_mq_clients:2::el7 | Package registry (OSV) |
| red hat:rubygem-qpid_proton | 0:0.33.0-6.el7_9 · Red Hat:a_mq_clients:2::el7 | Package registry (OSV) |
| rocky linux:libdb | 0:5.3.28-42.el8_4 · Rocky Linux:8 | Package registry (OSV) |
| suse:netty | 4.1.44.Final-150300.4.3.2 · SUSE:Manager Server Module 4.2 | Package 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.
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-22-0016 · Jan 7, 2022(IBM Güvenlik Zafiyeti)
- TR-21-0949 · Nov 25, 2021(IBM Güvenlik Bülteni Yayınladı)
- TR-21-0557 · Jul 7, 2021(IBM Güvenlik Bülteni Yayınladı)
- TR-21-0331 · Apr 21, 2021(Oracle Güvenlik Uyarısı Yayınladı)
Not on record for this CVE: EPSS history · researcher credit · variant or chain candidate · public bounty program.
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- none
- Availability
- none
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- None
- Availability impact
- None
Weakness class (CWE)
CWE-378 · Creation of Temporary File With Insecure PermissionsCVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
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.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log (2)
- SSVC exploitation— → none
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (19 more)Show less
- lists.apache.org/thread.html/r0053443ce19ff125981559f8c51cf66e3ab4350f47812b8cf0733a05%40%3Cdev.kafka.apache.org%3E
- lists.apache.org/thread.html/r02e467123d45006a1dda20a38349e9c74c3a4b53e2e07be0939ecb3f%40%3Cdev.ranger.apache.org%3E
- lists.apache.org/thread.html/r0857b613604c696bf9743f0af047360baaded48b1c75cf6945a083c5%40%3Cjira.kafka.apache.org%3E
- lists.apache.org/thread.html/r10308b625e49d4e9491d7e079606ca0df2f0a4d828f1ad1da64ba47b%40%3Cjira.kafka.apache.org%3E
- lists.apache.org/thread.html/r1908a34b9cc7120e5c19968a116ddbcffea5e9deb76c2be4fa461904%40%3Cdev.zookeeper.apache.org%3E
- lists.apache.org/thread.html/r2748097ea4b774292539cf3de6e3b267fc7a88d6c8ec40f4e2e87bd4%40%3Cdev.kafka.apache.org%3E
- lists.apache.org/thread.html/r2936730ef0a06e724b96539bc7eacfcd3628987c16b1b99c790e7b87%40%3Cissues.zookeeper.apache.org%3E
- lists.apache.org/thread.html/r2fda4dab73097051977f2ab818f75e04fbcb15bb1003c8530eac1059%40%3Cjira.kafka.apache.org%3E
- lists.apache.org/thread.html/r326ec431f06eab7cb7113a7a338e59731b8d556d05258457f12bac1b%40%3Cdev.kafka.apache.org%3E
- lists.apache.org/thread.html/r4efed2c501681cb2e8d629da16e48d9eac429624fd4c9a8c6b8e7020%40%3Cdev.tinkerpop.apache.org%3E
- lists.apache.org/thread.html/r584cf871f188c406d8bd447ff4e2fd9817fca862436c064d0951a071%40%3Ccommits.pulsar.apache.org%3E
- lists.apache.org/thread.html/r59bac5c09f7a4179b9e2460e8f41c278aaf3b9a21cc23678eb893e41%40%3Cjira.kafka.apache.org%3E
- lists.apache.org/thread.html/r5bf303d7c04da78f276765da08559fdc62420f1df539b277ca31f63b%40%3Cissues.zookeeper.apache.org%3E
- lists.apache.org/thread.html/r5c701840aa2845191721e39821445e1e8c59711e71942b7796a6ec29%40%3Cusers.activemq.apache.org%3E
- lists.apache.org/thread.html/r5e4a540089760c8ecc2c411309d74264f1dad634ad93ad583ca16214%40%3Ccommits.kafka.apache.org%3E
- lists.apache.org/thread.html/r5e66e286afb5506cdfe9bbf68a323e8d09614f6d1ddc806ed0224700%40%3Cjira.kafka.apache.org%3E
- lists.apache.org/thread.html/r71dbb66747ff537640bb91eb0b2b24edef21ac07728097016f58b01f%40%3Ccommits.kafka.apache.org%3E
- lists.apache.org/thread.html/r743149dcc8db1de473e6bff0b3ddf10140a7357bc2add75f7d1fbb12%40%3Cdev.zookeeper.apache.org%3E
- lists.apache.org/thread.html/r790c2926efcd062067eb18fde2486527596d7275381cfaff2f7b3890%40%3Cissues.bookkeeper.apache.org%3E
Vendor advisories and official records. Exploit/PoC links are deliberately left out.