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

CVE-2020-16127 (GCVE-0-2020-16127)

Vulnerability from cvelistv5 – Published: 2020-11-11 04:10 – Updated: 2024-09-16 17:58
VLAI
Title
accountsservice .pam_environment infinite loop
Summary
An Ubuntu-specific modification to AccountsService in versions before 0.6.55-0ubuntu13.2, among other earlier versions, would perform unbounded read operations on user-controlled ~/.pam_environment files, allowing an infinite loop if /dev/zero is symlinked to this location.
Severity
2.8 (Low)
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L
CWE
  • CWE-20 - Improper Input Validation
Assigner
References
Impacted products
Vendor Product Version CPE status
Freedesktop accountsservice Affected: 0.6.35-0ubuntu7.3 , < 0.6.35-0ubuntu7.3+esm2 (custom)
Affected: 0.6.40-2ubuntu11 , < 0.6.40-2ubuntu11.6 (custom)
Affected: 0.6.45-1ubuntu1 , < 0.6.45-1ubuntu1.3 (custom)
Affected: 0.6.55-0ubuntu , < 0.6.55-0ubuntu12~20.04.4 (custom)
Affected: 0.6.55-0ubuntu13 , < 0.6.55-0ubuntu13.2 (custom)
guessed Create a notification for this product.
Date Public
2020-11-03 00:00
Credits
Kevin Backhouse
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T13:37:53.922Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://securitylab.github.com/advisories/GHSL-2020-187-accountsservice-drop-privs-DOS"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "accountsservice",
          "vendor": "Freedesktop",
          "versions": [
            {
              "lessThan": "0.6.35-0ubuntu7.3+esm2",
              "status": "affected",
              "version": "0.6.35-0ubuntu7.3",
              "versionType": "custom"
            },
            {
              "lessThan": "0.6.40-2ubuntu11.6",
              "status": "affected",
              "version": "0.6.40-2ubuntu11",
              "versionType": "custom"
            },
            {
              "lessThan": "0.6.45-1ubuntu1.3",
              "status": "affected",
              "version": "0.6.45-1ubuntu1",
              "versionType": "custom"
            },
            {
              "lessThan": "0.6.55-0ubuntu12~20.04.4",
              "status": "affected",
              "version": "0.6.55-0ubuntu",
              "versionType": "custom"
            },
            {
              "lessThan": "0.6.55-0ubuntu13.2",
              "status": "affected",
              "version": "0.6.55-0ubuntu13",
              "versionType": "custom"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Kevin Backhouse"
        }
      ],
      "datePublic": "2020-11-03T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "An Ubuntu-specific modification to AccountsService in versions before 0.6.55-0ubuntu13.2, among other earlier versions, would perform unbounded read operations on user-controlled ~/.pam_environment files, allowing an infinite loop if /dev/zero is symlinked to this location."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "LOW",
            "baseScore": 2.8,
            "baseSeverity": "LOW",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-20",
              "description": "CWE-20 Improper Input Validation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2020-11-11T04:10:15.000Z",
        "orgId": "cc1ad9ee-3454-478d-9317-d3e869d708bc",
        "shortName": "canonical"
      },
      "references": [
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://securitylab.github.com/advisories/GHSL-2020-187-accountsservice-drop-privs-DOS"
        }
      ],
      "source": {
        "advisory": "https://usn.ubuntu.com/usn/usn-4616-1",
        "defect": [
          "https://bugs.launchpad.net/ubuntu/+source/accountsservice/+bug/1900255"
        ],
        "discovery": "EXTERNAL"
      },
      "title": "accountsservice .pam_environment infinite loop",
      "x_generator": {
        "engine": "Vulnogram 0.0.9"
      },
      "x_legacyV4Record": {
        "CVE_data_meta": {
          "ASSIGNER": "security@ubuntu.com",
          "DATE_PUBLIC": "2020-11-03T00:00:00.000Z",
          "ID": "CVE-2020-16127",
          "STATE": "PUBLIC",
          "TITLE": "accountsservice .pam_environment infinite loop"
        },
        "affects": {
          "vendor": {
            "vendor_data": [
              {
                "product": {
                  "product_data": [
                    {
                      "product_name": "accountsservice",
                      "version": {
                        "version_data": [
                          {
                            "version_affected": "\u003c",
                            "version_name": "0.6.35-0ubuntu7.3",
                            "version_value": "0.6.35-0ubuntu7.3+esm2"
                          },
                          {
                            "version_affected": "\u003c",
                            "version_name": "0.6.40-2ubuntu11",
                            "version_value": "0.6.40-2ubuntu11.6"
                          },
                          {
                            "version_affected": "\u003c",
                            "version_name": "0.6.45-1ubuntu1",
                            "version_value": "0.6.45-1ubuntu1.3"
                          },
                          {
                            "version_affected": "\u003c",
                            "version_name": "0.6.55-0ubuntu",
                            "version_value": "0.6.55-0ubuntu12~20.04.4"
                          },
                          {
                            "version_affected": "\u003c",
                            "version_name": "0.6.55-0ubuntu13",
                            "version_value": "0.6.55-0ubuntu13.2"
                          }
                        ]
                      }
                    }
                  ]
                },
                "vendor_name": "Freedesktop"
              }
            ]
          }
        },
        "credit": [
          {
            "lang": "eng",
            "value": "Kevin Backhouse"
          }
        ],
        "data_format": "MITRE",
        "data_type": "CVE",
        "data_version": "4.0",
        "description": {
          "description_data": [
            {
              "lang": "eng",
              "value": "An Ubuntu-specific modification to AccountsService in versions before 0.6.55-0ubuntu13.2, among other earlier versions, would perform unbounded read operations on user-controlled ~/.pam_environment files, allowing an infinite loop if /dev/zero is symlinked to this location."
            }
          ]
        },
        "generator": {
          "engine": "Vulnogram 0.0.9"
        },
        "impact": {
          "cvss": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "LOW",
            "baseScore": 2.8,
            "baseSeverity": "LOW",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L",
            "version": "3.1"
          }
        },
        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "eng",
                  "value": "CWE-20 Improper Input Validation"
                }
              ]
            }
          ]
        },
        "references": {
          "reference_data": [
            {
              "name": "https://securitylab.github.com/advisories/GHSL-2020-187-accountsservice-drop-privs-DOS",
              "refsource": "MISC",
              "url": "https://securitylab.github.com/advisories/GHSL-2020-187-accountsservice-drop-privs-DOS"
            }
          ]
        },
        "source": {
          "advisory": "https://usn.ubuntu.com/usn/usn-4616-1",
          "defect": [
            "https://bugs.launchpad.net/ubuntu/+source/accountsservice/+bug/1900255"
          ],
          "discovery": "EXTERNAL"
        }
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "cc1ad9ee-3454-478d-9317-d3e869d708bc",
    "assignerShortName": "canonical",
    "cveId": "CVE-2020-16127",
    "datePublished": "2020-11-11T04:10:15.512Z",
    "dateReserved": "2020-07-29T00:00:00.000Z",
    "dateUpdated": "2024-09-16T17:58:49.219Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2020-16127",
      "date": "2026-09-16",
      "epss": "0.00414",
      "percentile": "0.35112"
    },
    "fkie_nvd": {
      "configurations": "[{\"nodes\": [{\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": true, \"criteria\": \"cpe:2.3:a:freedesktop:accountsservice:*:*:*:*:*:*:*:*\", \"versionEndExcluding\": \"0.6.55\", \"matchCriteriaId\": \"9A297546-6EAD-40F9-819E-E3604CF93964\"}]}]}]",
      "descriptions": "[{\"lang\": \"en\", \"value\": \"An Ubuntu-specific modification to AccountsService in versions before 0.6.55-0ubuntu13.2, among other earlier versions, would perform unbounded read operations on user-controlled ~/.pam_environment files, allowing an infinite loop if /dev/zero is symlinked to this location.\"}, {\"lang\": \"es\", \"value\": \"Una modificaci\\u00f3n espec\\u00edfica de Ubuntu para AccountsService en versiones anteriores a 0.6.55-0ubuntu13.2, entre otras versiones anteriores, llevar\\u00eda a cabo operaciones de lectura ilimitadas en archivos ~/.pam_environment controlados por el usuario, permitiendo un bucle infinito si /dev/zero est\\u00e1 enlazado simb\\u00f3licamente a esta ubicaci\\u00f3n\"}]",
      "id": "CVE-2020-16127",
      "lastModified": "2024-11-21T05:06:48.983",
      "metrics": "{\"cvssMetricV31\": [{\"source\": \"security@ubuntu.com\", \"type\": \"Secondary\", \"cvssData\": {\"version\": \"3.1\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L\", \"baseScore\": 2.8, \"baseSeverity\": \"LOW\", \"attackVector\": \"LOCAL\", \"attackComplexity\": \"LOW\", \"privilegesRequired\": \"LOW\", \"userInteraction\": \"REQUIRED\", \"scope\": \"UNCHANGED\", \"confidentialityImpact\": \"NONE\", \"integrityImpact\": \"NONE\", \"availabilityImpact\": \"LOW\"}, \"exploitabilityScore\": 1.3, \"impactScore\": 1.4}, {\"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": "2020-11-11T04:15:12.177",
      "references": "[{\"url\": \"https://securitylab.github.com/advisories/GHSL-2020-187-accountsservice-drop-privs-DOS\", \"source\": \"security@ubuntu.com\", \"tags\": [\"Exploit\", \"Third Party Advisory\"]}, {\"url\": \"https://securitylab.github.com/advisories/GHSL-2020-187-accountsservice-drop-privs-DOS\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\", \"tags\": [\"Exploit\", \"Third Party Advisory\"]}]",
      "sourceIdentifier": "security@ubuntu.com",
      "vulnStatus": "Modified",
      "weaknesses": "[{\"source\": \"security@ubuntu.com\", \"type\": \"Secondary\", \"description\": [{\"lang\": \"en\", \"value\": \"CWE-20\"}]}, {\"source\": \"nvd@nist.gov\", \"type\": \"Primary\", \"description\": [{\"lang\": \"en\", \"value\": \"CWE-835\"}]}]"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2020-16127\",\"sourceIdentifier\":\"security@ubuntu.com\",\"published\":\"2020-11-11T04:15:12.177\",\"lastModified\":\"2024-11-21T05:06:48.983\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"An Ubuntu-specific modification to AccountsService in versions before 0.6.55-0ubuntu13.2, among other earlier versions, would perform unbounded read operations on user-controlled ~/.pam_environment files, allowing an infinite loop if /dev/zero is symlinked to this location.\"},{\"lang\":\"es\",\"value\":\"Una modificaci\u00f3n espec\u00edfica de Ubuntu para AccountsService en versiones anteriores a 0.6.55-0ubuntu13.2, entre otras versiones anteriores, llevar\u00eda a cabo operaciones de lectura ilimitadas en archivos ~/.pam_environment controlados por el usuario, permitiendo un bucle infinito si /dev/zero est\u00e1 enlazado simb\u00f3licamente a esta ubicaci\u00f3n\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security@ubuntu.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L\",\"baseScore\":2.8,\"baseSeverity\":\"LOW\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"REQUIRED\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"LOW\"},\"exploitabilityScore\":1.3,\"impactScore\":1.4},{\"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\":\"security@ubuntu.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-20\"}]},{\"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:freedesktop:accountsservice:*:*:*:*:*:*:*:*\",\"versionEndExcluding\":\"0.6.55\",\"matchCriteriaId\":\"9A297546-6EAD-40F9-819E-E3604CF93964\"}]}]}],\"references\":[{\"url\":\"https://securitylab.github.com/advisories/GHSL-2020-187-accountsservice-drop-privs-DOS\",\"source\":\"security@ubuntu.com\",\"tags\":[\"Exploit\",\"Third Party Advisory\"]},{\"url\":\"https://securitylab.github.com/advisories/GHSL-2020-187-accountsservice-drop-privs-DOS\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Exploit\",\"Third Party Advisory\"]}]}}",
    "suse_vex": {
      "aggregate_severity": "low",
      "current_release_date": "2025-10-07T02:55:01Z",
      "cve": "CVE-2020-16127",
      "id": "CVE-2020-16127",
      "initial_release_date": "2023-02-15T03:55:55Z",
      "product_status:known_not_affected": "212",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2020-16127",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2020-16127.json",
      "version": "12"
    }
  }
}



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.