5.5
MEDIUM
CVE-2021-3996
Linux Util-Linux FUSE Unmount Privilege Escalation Vulnerability
Description

A logic error was found in the libmount library of util-linux in the function that allows an unprivileged user to unmount a FUSE filesystem. This flaw allows a local user on a vulnerable system to unmount other users' filesystems that are either world-writable themselves (like /tmp) or mounted in a world-writable directory. An attacker may use this flaw to cause a denial of service to applications that use the affected filesystems.

INFO

Published Date :

Aug. 23, 2022, 8:15 p.m.

Last Modified :

Oct. 15, 2024, 4:35 p.m.

Remotely Exploitable :

No

Impact Score :

3.6

Exploitability Score :

1.8
Public PoC/Exploit Available at Github

CVE-2021-3996 has a 1 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

Affected Products

The following products are affected by CVE-2021-3996 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Fedoraproject fedora
1 Kernel util-linux
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-3996.

URL Resource
http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html Third Party Advisory
http://seclists.org/fulldisclosure/2022/Dec/4 Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2022/11/30/2 Mailing List Third Party Advisory
https://access.redhat.com/security/cve/CVE-2021-3996 Issue Tracking Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2024628 Issue Tracking Patch Third Party Advisory
https://github.com/util-linux/util-linux/commit/166e87368ae88bf31112a30e078cceae637f4cdb Patch Third Party Advisory
https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotes Release Notes Vendor Advisory
https://security.gentoo.org/glsa/202401-08
https://security.netapp.com/advisory/ntap-20221209-0002/ Broken Link Third Party Advisory
https://www.openwall.com/lists/oss-security/2022/01/24/2 Exploit Mailing List Patch Third Party Advisory

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

None

HCL Smarty

Updated: 2 years, 8 months ago
0 stars 0 fork 0 watcher
Born at : Sept. 26, 2021, 4:49 p.m. This repo has been linked 3 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-3996 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-3996 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Oct. 15, 2024

    Action Type Old Value New Value
    Added CVSS V3.1 CISA-ADP AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Jan. 07, 2024

    Action Type Old Value New Value
    Added Reference Red Hat, Inc. https://security.gentoo.org/glsa/202401-08 [No types assigned]
  • Modified Analysis by [email protected]

    Jan. 26, 2023

    Action Type Old Value New Value
    Changed Reference Type http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html No Types Assigned http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html Third Party Advisory
    Changed Reference Type http://seclists.org/fulldisclosure/2022/Dec/4 No Types Assigned http://seclists.org/fulldisclosure/2022/Dec/4 Mailing List, Third Party Advisory
    Changed Reference Type http://www.openwall.com/lists/oss-security/2022/11/30/2 No Types Assigned http://www.openwall.com/lists/oss-security/2022/11/30/2 Mailing List, Third Party Advisory
    Changed Reference Type https://security.netapp.com/advisory/ntap-20221209-0002/ No Types Assigned https://security.netapp.com/advisory/ntap-20221209-0002/ Broken Link, Third Party Advisory
  • CVE Modified by [email protected]

    Dec. 09, 2022

    Action Type Old Value New Value
    Added Reference https://security.netapp.com/advisory/ntap-20221209-0002/ [No Types Assigned]
  • CVE Modified by [email protected]

    Dec. 09, 2022

    Action Type Old Value New Value
    Added Reference http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html [No Types Assigned]
  • CVE Modified by [email protected]

    Dec. 09, 2022

    Action Type Old Value New Value
    Added Reference http://seclists.org/fulldisclosure/2022/Dec/4 [No Types Assigned]
  • CVE Modified by [email protected]

    Dec. 01, 2022

    Action Type Old Value New Value
    Added Reference http://www.openwall.com/lists/oss-security/2022/11/30/2 [No Types Assigned]
  • Reanalysis by [email protected]

    Nov. 14, 2022

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:kernel:util-linux:*:*:*:*:*:*:*:* versions up to (excluding) 2.37.3 OR *cpe:2.3:a:kernel:util-linux:*:*:*:*:*:*:*:* versions from (including) 2.34 up to (excluding) 2.37.3
  • Initial Analysis by [email protected]

    Aug. 29, 2022

    Action Type Old Value New Value
    Added CVSS V3.1 NIST AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
    Changed Reference Type https://access.redhat.com/security/cve/CVE-2021-3996 No Types Assigned https://access.redhat.com/security/cve/CVE-2021-3996 Issue Tracking, Third Party Advisory
    Changed Reference Type https://bugzilla.redhat.com/show_bug.cgi?id=2024628 No Types Assigned https://bugzilla.redhat.com/show_bug.cgi?id=2024628 Issue Tracking, Patch, Third Party Advisory
    Changed Reference Type https://github.com/util-linux/util-linux/commit/166e87368ae88bf31112a30e078cceae637f4cdb No Types Assigned https://github.com/util-linux/util-linux/commit/166e87368ae88bf31112a30e078cceae637f4cdb Patch, Third Party Advisory
    Changed Reference Type https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotes No Types Assigned https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotes Release Notes, Vendor Advisory
    Changed Reference Type https://www.openwall.com/lists/oss-security/2022/01/24/2 No Types Assigned https://www.openwall.com/lists/oss-security/2022/01/24/2 Exploit, Mailing List, Patch, Third Party Advisory
    Added CWE NIST CWE-552
    Added CPE Configuration OR *cpe:2.3:a:kernel:util-linux:*:*:*:*:*:*:*:* versions up to (excluding) 2.37.3
    Added CPE Configuration OR *cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-3996 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-3996 weaknesses.

Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.04 }} 0.00%

score

0.05635

percentile

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability