CVE-2021-47084: Software Security Vulnerability Vulnerability

UNKNOWN
Advisory Identifier: GHSA-7xj5-h6cr-5xf4
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Advisory Summary

CVE-2021-47084 is a security vulnerability vulnerability (General Security Weakness) affecting Software libraries in the Maven ecosystem. Remediation is available in the latest vendor maintenance releases.

CVE-2021-47084 at a Glance

CVE Identifier CVE-2021-47084
GHSA Identifier GHSA-7xj5-h6cr-5xf4
Severity N/A
CVSS v3.1 Base Score N/A
CWE Classification General Security Weakness
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2021-47084

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2021-47084, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under General Security Weakness. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

In the Linux kernel, the following vulnerability has been resolved: hamradio: defer ax25 kfree after unregister_netdev There is a possible race condition (use-after-free) like below (USE) | (FREE) ax25_sendmsg | ax25_queue_xmit | dev_queue_xmit | __dev_queue_xmit | __dev_xmit_skb | sch_direct_xmit | ... xmit_one | netdev_start_xmit | tty_ldisc_kill __netdev_start_xmit | mkiss_close ax_xmit | kfree ax_encaps | | Even though there are two synchronization primitives before the kfree: 1. wait_for_completion(&ax->dead). This can prevent the race with routines from mkiss_ioctl. However, it cannot stop the routine coming from upper layer, i.e., the ax25_sendmsg. 2. netif_stop_queue(ax->dev). It seems that this line of code aims to halt the transmit queue but it fails to stop the routine that already being xmit. This patch reorder the kfree after the unregister_netdev to avoid the possible UAF as the unregister_netdev() is well synchronized and won't return if there is a running routine.

References

NVD — CVE-2021-47084 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-47084
git.kernel.org/stable/c/3e0588c291... WEB
https://git.kernel.org/stable/c/3e0588c291d6ce225f2b891753ca41d45ba42469
git.kernel.org/stable/c/450121075a... WEB
https://git.kernel.org/stable/c/450121075a6a6f1d50f97225d3396315309d61a1
git.kernel.org/stable/c/896193a02a... WEB
https://git.kernel.org/stable/c/896193a02a2981e60c40d4614fd095ce92135ccd
git.kernel.org/stable/c/8a1a314965... WEB
https://git.kernel.org/stable/c/8a1a314965a17c62084a056b4f2cb7a770854c90
git.kernel.org/stable/c/b5b193d0c6... WEB
https://git.kernel.org/stable/c/b5b193d0c67180fefdc664650138e3b7959df615
git.kernel.org/stable/c/cb6c99aedd... WEB
https://git.kernel.org/stable/c/cb6c99aedd2c843056a598a8907a6128cb07603b
git.kernel.org/stable/c/eaa816a86e... WEB
https://git.kernel.org/stable/c/eaa816a86e629cbcc0a94f38391fee09231628c7
git.kernel.org/stable/c/ef5f7bfa19... WEB
https://git.kernel.org/stable/c/ef5f7bfa19e3fc366f4c6d1a841ceaddf7a9f5d4

Frequently Asked Questions

What is CVE-2021-47084?
CVE-2021-47084 is a security vulnerability in Software classified as a security vulnerability vulnerability under General Security Weakness.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2021-47084?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What CWE is associated with CVE-2021-47084?
CVE-2021-47084 is classified under General Security Weakness.
How can I check Maven dependencies for CVE-2021-47084?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
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  "schema_version" : "1.4.0",
  "id" : "GHSA-7xj5-h6cr-5xf4",
  "modified" : "2024-03-04T18:30:37Z",
  "published" : "2024-03-04T18:30:37Z",
  "aliases" : [ "CVE-2021-47084" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nhamradio: defer ax25 kfree after unregister_netdev\n\nThere is a possible race condition (use-after-free) like below\n\n (USE)                       |  (FREE)\nax25_sendmsg                 |\n ax25_queue_xmit             |\n  dev_queue_xmit             |\n   __dev_queue_xmit          |\n    __dev_xmit_skb           |\n     sch_direct_xmit         | ...\n      xmit_one               |\n       netdev_start_xmit     | tty_ldisc_kill\n        __netdev_start_xmit  |  mkiss_close\n         ax_xmit             |   kfree\n          ax_encaps          |\n                             |\n\nEven though there are two synchronization primitives before the kfree:\n1. wait_for_completion(&ax->dead). This can prevent the race with\nroutines from mkiss_ioctl. However, it cannot stop the routine coming\nfrom upper layer, i.e., the ax25_sendmsg.\n\n2. netif_stop_queue(ax->dev). It seems that this line of code aims to\nhalt the transmit queue but it fails to stop the routine that already\nbeing xmit.\n\nThis patch reorder the kfree after the unregister_netdev to avoid the\npossible UAF as the unregister_netdev() is well synchronized and won't\nreturn if there is a running routine.",
  "severity" : [ ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
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    "url" : "https://git.kernel.org/stable/c/3e0588c291d6ce225f2b891753ca41d45ba42469"
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    "type" : "WEB",
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    "url" : "https://git.kernel.org/stable/c/ef5f7bfa19e3fc366f4c6d1a841ceaddf7a9f5d4"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : null,
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2024-03-04T18:15:07Z"
  }
}