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FKIE_CVE-2021-3996

Vulnerability from fkie_nvd - Published: 2022-08-23 20:15 - Updated: 2026-06-17 04:06
Severity
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
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.
References
secalert@redhat.comhttp://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.htmlThird Party Advisory
secalert@redhat.comhttp://seclists.org/fulldisclosure/2022/Dec/4Mailing List, Third Party Advisory
secalert@redhat.comhttp://www.openwall.com/lists/oss-security/2022/11/30/2Mailing List, Third Party Advisory
secalert@redhat.comhttps://access.redhat.com/security/cve/CVE-2021-3996Issue Tracking, Third Party Advisory
secalert@redhat.comhttps://bugzilla.redhat.com/show_bug.cgi?id=2024628Issue Tracking, Patch, Third Party Advisory
secalert@redhat.comhttps://github.com/util-linux/util-linux/commit/166e87368ae88bf31112a30e078cceae637f4cdbPatch, Third Party Advisory
secalert@redhat.comhttps://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotesRelease Notes, Vendor Advisory
secalert@redhat.comhttps://security.gentoo.org/glsa/202401-08
secalert@redhat.comhttps://security.netapp.com/advisory/ntap-20221209-0002/Broken Link, Third Party Advisory
secalert@redhat.comhttps://www.openwall.com/lists/oss-security/2022/01/24/2Exploit, Mailing List, Patch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.htmlThird Party Advisory
af854a3a-2127-422b-91ae-364da2661108http://seclists.org/fulldisclosure/2022/Dec/4Mailing List, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108http://www.openwall.com/lists/oss-security/2022/11/30/2Mailing List, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://access.redhat.com/security/cve/CVE-2021-3996Issue Tracking, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://bugzilla.redhat.com/show_bug.cgi?id=2024628Issue Tracking, Patch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://github.com/util-linux/util-linux/commit/166e87368ae88bf31112a30e078cceae637f4cdbPatch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotesRelease Notes, Vendor Advisory
af854a3a-2127-422b-91ae-364da2661108https://security.gentoo.org/glsa/202401-08
af854a3a-2127-422b-91ae-364da2661108https://security.netapp.com/advisory/ntap-20221209-0002/Broken Link, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://www.openwall.com/lists/oss-security/2022/01/24/2Exploit, Mailing List, Patch, Third Party Advisory
Impacted products
Vendor Product Version
kernel util-linux *
fedoraproject fedora 35
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "util-linux",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "Fixed in util-linux v2.37.3"
            }
          ]
        }
      ],
      "source": "secalert@redhat.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:kernel:util-linux:*:*:*:*:*:*:*:*",
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              "versionEndExcluding": "2.37.3",
              "versionStartIncluding": "2.34",
              "vulnerable": true
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  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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\u0027 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."
    },
    {
      "lang": "es",
      "value": "Se ha encontrado un error l\u00f3gico en la biblioteca libmount de util-linux en la funci\u00f3n que permite a un usuario no privilegiado desmontar un sistema de archivos FUSE. Este fallo permite a un usuario local en un sistema vulnerable desmontar los sistemas de archivos de otros usuarios que son de escritura mundial (como /tmp) o que est\u00e1n montados en un directorio de escritura mundial. Un atacante puede usar este fallo para causar una denegaci\u00f3n de servicio a las aplicaciones que usan los sistemas de archivos afectados."
    }
  ],
  "id": "CVE-2021-3996",
  "lastModified": "2026-06-17T04:06:21.753",
  "metrics": {
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          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
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          "integrityImpact": "NONE",
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          "role": "CISA Coordinator",
          "timestamp": "2024-03-04T21:16:28.797475Z",
          "version": "2.0.3"
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  ]
}



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Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.