GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2021-3468 (GCVE-0-2021-3468)

Vulnerability from cvelistv5 – Published: 2021-06-02 15:09 – Updated: 2025-02-13 16:28
VLAI
Summary
A flaw was found in avahi in versions 0.6 up to 0.8. The event used to signal the termination of the client connection on the avahi Unix socket is not correctly handled in the client_work function, allowing a local attacker to trigger an infinite loop. The highest threat from this vulnerability is to the availability of the avahi service, which becomes unresponsive after this flaw is triggered.
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE
Assigner
References
Impacted products
Vendor Product Version CPE status
n/a avahi Affected: All avahi versions 0.6 up to 0.8
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-03T16:53:17.602Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1939614"
          },
          {
            "name": "[debian-lts-announce] 20220607 [SECURITY] [DLA 3047-1] avahi security update",
            "tags": [
              "mailing-list",
              "x_refsource_MLIST",
              "x_transferred"
            ],
            "url": "https://lists.debian.org/debian-lts-announce/2022/06/msg00009.html"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://lists.debian.org/debian-lts-announce/2023/06/msg00028.html"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "avahi",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "All avahi versions 0.6 up to 0.8"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "A flaw was found in avahi in versions 0.6 up to 0.8. The event used to signal the termination of the client connection on the avahi Unix socket is not correctly handled in the client_work function, allowing a local attacker to trigger an infinite loop. The highest threat from this vulnerability is to the availability of the avahi service, which becomes unresponsive after this flaw is triggered."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-835",
              "description": "CWE-835",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2023-06-22T00:06:10.695Z",
        "orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
        "shortName": "redhat"
      },
      "references": [
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1939614"
        },
        {
          "name": "[debian-lts-announce] 20220607 [SECURITY] [DLA 3047-1] avahi security update",
          "tags": [
            "mailing-list",
            "x_refsource_MLIST"
          ],
          "url": "https://lists.debian.org/debian-lts-announce/2022/06/msg00009.html"
        },
        {
          "url": "https://lists.debian.org/debian-lts-announce/2023/06/msg00028.html"
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
    "assignerShortName": "redhat",
    "cveId": "CVE-2021-3468",
    "datePublished": "2021-06-02T15:09:21.000Z",
    "dateReserved": "2021-03-26T00:00:00.000Z",
    "dateUpdated": "2025-02-13T16:28:23.614Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2021-3468",
      "date": "2026-09-16",
      "epss": "0.00443",
      "percentile": "0.37661"
    },
    "fkie_nvd": {
      "configurations": "[{\"nodes\": [{\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": true, \"criteria\": \"cpe:2.3:a:avahi:avahi:*:*:*:*:*:*:*:*\", \"versionStartIncluding\": \"0.6\", \"versionEndIncluding\": \"0.8\", \"matchCriteriaId\": \"1A5E35AD-158F-4E70-8C3A-3E27BF3406F4\"}]}]}, {\"nodes\": [{\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": true, \"criteria\": \"cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"DEECE5FC-CACF-4496-A3E7-164736409252\"}]}]}]",
      "descriptions": "[{\"lang\": \"en\", \"value\": \"A flaw was found in avahi in versions 0.6 up to 0.8. The event used to signal the termination of the client connection on the avahi Unix socket is not correctly handled in the client_work function, allowing a local attacker to trigger an infinite loop. The highest threat from this vulnerability is to the availability of the avahi service, which becomes unresponsive after this flaw is triggered.\"}, {\"lang\": \"es\", \"value\": \"Se ha encontrado un fallo en avahi en versiones 0.6 hasta 0.8. El evento usado para se\\u00f1alar la terminaci\\u00f3n de la conexi\\u00f3n del cliente en el socket Unix de avahi no se maneja correctamente en la funci\\u00f3n client_work, permitiendo a un atacante local desencadenar un bucle infinito. La mayor amenaza de esta vulnerabilidad es la disponibilidad del servicio avahi, que deja de responder despu\\u00e9s de que este fallo es activado\"}]",
      "id": "CVE-2021-3468",
      "lastModified": "2024-11-21T06:21:36.953",
      "metrics": "{\"cvssMetricV31\": [{\"source\": \"nvd@nist.gov\", \"type\": \"Primary\", \"cvssData\": {\"version\": \"3.1\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H\", \"baseScore\": 5.5, \"baseSeverity\": \"MEDIUM\", \"attackVector\": \"LOCAL\", \"attackComplexity\": \"LOW\", \"privilegesRequired\": \"LOW\", \"userInteraction\": \"NONE\", \"scope\": \"UNCHANGED\", \"confidentialityImpact\": \"NONE\", \"integrityImpact\": \"NONE\", \"availabilityImpact\": \"HIGH\"}, \"exploitabilityScore\": 1.8, \"impactScore\": 3.6}], \"cvssMetricV2\": [{\"source\": \"nvd@nist.gov\", \"type\": \"Primary\", \"cvssData\": {\"version\": \"2.0\", \"vectorString\": \"AV:L/AC:L/Au:N/C:N/I:N/A:P\", \"baseScore\": 2.1, \"accessVector\": \"LOCAL\", \"accessComplexity\": \"LOW\", \"authentication\": \"NONE\", \"confidentialityImpact\": \"NONE\", \"integrityImpact\": \"NONE\", \"availabilityImpact\": \"PARTIAL\"}, \"baseSeverity\": \"LOW\", \"exploitabilityScore\": 3.9, \"impactScore\": 2.9, \"acInsufInfo\": false, \"obtainAllPrivilege\": false, \"obtainUserPrivilege\": false, \"obtainOtherPrivilege\": false, \"userInteractionRequired\": false}]}",
      "published": "2021-06-02T16:15:08.960",
      "references": "[{\"url\": \"https://bugzilla.redhat.com/show_bug.cgi?id=1939614\", \"source\": \"secalert@redhat.com\", \"tags\": [\"Issue Tracking\"]}, {\"url\": \"https://lists.debian.org/debian-lts-announce/2022/06/msg00009.html\", \"source\": \"secalert@redhat.com\", \"tags\": [\"Mailing List\", \"Third Party Advisory\"]}, {\"url\": \"https://lists.debian.org/debian-lts-announce/2023/06/msg00028.html\", \"source\": \"secalert@redhat.com\"}, {\"url\": \"https://bugzilla.redhat.com/show_bug.cgi?id=1939614\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\", \"tags\": [\"Issue Tracking\"]}, {\"url\": \"https://lists.debian.org/debian-lts-announce/2022/06/msg00009.html\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\", \"tags\": [\"Mailing List\", \"Third Party Advisory\"]}, {\"url\": \"https://lists.debian.org/debian-lts-announce/2023/06/msg00028.html\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\"}]",
      "sourceIdentifier": "secalert@redhat.com",
      "vulnStatus": "Modified",
      "weaknesses": "[{\"source\": \"secalert@redhat.com\", \"type\": \"Secondary\", \"description\": [{\"lang\": \"en\", \"value\": \"CWE-835\"}]}, {\"source\": \"nvd@nist.gov\", \"type\": \"Primary\", \"description\": [{\"lang\": \"en\", \"value\": \"CWE-835\"}]}]"
    },
    "microsoft_vex": {
      "current_release_date": "2026-02-18T14:59:05.000Z",
      "cve": "CVE-2021-3468",
      "id": "msrc_CVE-2021-3468",
      "initial_release_date": "2021-06-02T00:00:00.000Z",
      "product_status:fixed": "3",
      "product_status:known_affected": "3",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "A flaw was found in avahi in versions 0.6 up to 0.8. The event used to signal the termination of the client connection on the avahi Unix socket is not correctly handled in the client_work function allowing a local attacker to trigger an infinite loop. The highest threat from this vulnerability is to the availability of the avahi service which becomes unresponsive after this flaw is triggered.",
      "url": "https://msrc.microsoft.com/csaf/vex/2021/msrc_cve-2021-3468.json",
      "version": "3"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2021-3468\",\"sourceIdentifier\":\"secalert@redhat.com\",\"published\":\"2021-06-02T16:15:08.960\",\"lastModified\":\"2024-11-21T06:21:36.953\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"A flaw was found in avahi in versions 0.6 up to 0.8. The event used to signal the termination of the client connection on the avahi Unix socket is not correctly handled in the client_work function, allowing a local attacker to trigger an infinite loop. The highest threat from this vulnerability is to the availability of the avahi service, which becomes unresponsive after this flaw is triggered.\"},{\"lang\":\"es\",\"value\":\"Se ha encontrado un fallo en avahi en versiones 0.6 hasta 0.8. El evento usado para se\u00f1alar la terminaci\u00f3n de la conexi\u00f3n del cliente en el socket Unix de avahi no se maneja correctamente en la funci\u00f3n client_work, permitiendo a un atacante local desencadenar un bucle infinito. La mayor amenaza de esta vulnerabilidad es la disponibilidad del servicio avahi, que deja de responder despu\u00e9s de que este fallo es activado\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":5.5,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":3.6}],\"cvssMetricV2\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"2.0\",\"vectorString\":\"AV:L/AC:L/Au:N/C:N/I:N/A:P\",\"baseScore\":2.1,\"accessVector\":\"LOCAL\",\"accessComplexity\":\"LOW\",\"authentication\":\"NONE\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"PARTIAL\"},\"baseSeverity\":\"LOW\",\"exploitabilityScore\":3.9,\"impactScore\":2.9,\"acInsufInfo\":false,\"obtainAllPrivilege\":false,\"obtainUserPrivilege\":false,\"obtainOtherPrivilege\":false,\"userInteractionRequired\":false}]},\"weaknesses\":[{\"source\":\"secalert@redhat.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-835\"}]},{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-835\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:avahi:avahi:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"0.6\",\"versionEndIncluding\":\"0.8\",\"matchCriteriaId\":\"1A5E35AD-158F-4E70-8C3A-3E27BF3406F4\"}]}]},{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"DEECE5FC-CACF-4496-A3E7-164736409252\"}]}]}],\"references\":[{\"url\":\"https://bugzilla.redhat.com/show_bug.cgi?id=1939614\",\"source\":\"secalert@redhat.com\",\"tags\":[\"Issue Tracking\"]},{\"url\":\"https://lists.debian.org/debian-lts-announce/2022/06/msg00009.html\",\"source\":\"secalert@redhat.com\",\"tags\":[\"Mailing List\",\"Third Party Advisory\"]},{\"url\":\"https://lists.debian.org/debian-lts-announce/2023/06/msg00028.html\",\"source\":\"secalert@redhat.com\"},{\"url\":\"https://bugzilla.redhat.com/show_bug.cgi?id=1939614\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Issue Tracking\"]},{\"url\":\"https://lists.debian.org/debian-lts-announce/2022/06/msg00009.html\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Mailing List\",\"Third Party Advisory\"]},{\"url\":\"https://lists.debian.org/debian-lts-announce/2023/06/msg00028.html\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2025-11-21T14:51:13+00:00",
      "cve": "CVE-2021-3468",
      "id": "CVE-2021-3468",
      "initial_release_date": "2021-03-10T00:00:00+00:00",
      "product_status:fixed": "1608",
      "product_status:known_affected": "45",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "avahi: Local DoS by event-busy-loop from writing long lines to /run/avahi-daemon/socket",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-3468.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-05T17:12:55Z",
      "cve": "CVE-2021-3468",
      "id": "CVE-2021-3468",
      "initial_release_date": "2023-02-15T03:49:27Z",
      "product_status:known_affected": "301",
      "product_status:recommended": "1694",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2021-3468",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2021-3468.json",
      "version": "41"
    }
  }
}



Log in or create an account to share your comment.




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.