Vulnerability-Lookup

oesa-2021-1043

Vulnerability from osv_openeuler

Published

2021-03-05 11:04

Modified

2026-08-06 11:04

Summary

flatpak security update

Details

flatpak is a system for building, distributing and running sandboxed desktop applications on Linux. See https://wiki.gnome.org/Projects/SandboxedApps for more information.

Security Fix(es):

Flatpak is a system for building, distributing, and running sandboxed desktop applications on Linux. A bug was discovered in the flatpak-portal service that can allow sandboxed applications to execute arbitrary code on the host system (a sandbox escape). This sandbox-escape bug is present in versions from 0.11.4 and before fixed versions 1.8.5 and 1.9.4. The Flatpak portal D-Bus service (flatpak-portal, also known by its D-Bus service name org.freedesktop.portal.Flatpak) allows apps in a Flatpak sandbox to launch their own subprocesses in a new sandbox instance, either with the same security settings as the caller or with more restrictive security settings. For example, this is used in Flatpak-packaged web browsers such as Chromium to launch subprocesses that will process untrusted web content, and give those subprocesses a more restrictive sandbox than the browser itself. In vulnerable versions, the Flatpak portal service passes caller-specified environment variables to non-sandboxed processes on the host system, and in particular to the flatpak run command that is used to launch the new sandbox instance. A malicious or compromised Flatpak app could set environment variables that are trusted by the flatpak run command, and use them to execute arbitrary code that is not in a sandbox. As a workaround, this vulnerability can be mitigated by preventing the flatpak-portal service from starting, but that mitigation will prevent many Flatpak apps from working correctly. This is fixed in versions 1.8.5 and 1.9.4.(CVE-2021-21261)

Severity

8.8 (High)


                    
                      CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

References

URL

Type

	https://openeuler.org/en/security/safety-bulletin…	ADVISORY
	https://nvd.nist.gov/vuln/detail/CVE-2021-21261	ADVISORY

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "aarch64": [
          "flatpak-debugsource-1.0.3-3.oe1.aarch64.rpm",
          "flatpak-debuginfo-1.0.3-3.oe1.aarch64.rpm",
          "flatpak-devel-1.0.3-3.oe1.aarch64.rpm",
          "flatpak-1.0.3-3.oe1.aarch64.rpm",
          "flatpak-debugsource-1.0.3-3.oe1.aarch64.rpm",
          "flatpak-debuginfo-1.0.3-3.oe1.aarch64.rpm",
          "flatpak-devel-1.0.3-3.oe1.aarch64.rpm",
          "flatpak-1.0.3-3.oe1.aarch64.rpm"
        ],
        "noarch": [
          "flatpak-help-1.0.3-3.oe1.noarch.rpm",
          "flatpak-help-1.0.3-3.oe1.noarch.rpm"
        ],
        "src": [
          "flatpak-1.0.3-3.oe1.src.rpm",
          "flatpak-1.0.3-3.oe1.src.rpm"
        ],
        "x86_64": [
          "flatpak-devel-1.0.3-3.oe1.x86_64.rpm",
          "flatpak-debugsource-1.0.3-3.oe1.x86_64.rpm",
          "flatpak-debuginfo-1.0.3-3.oe1.x86_64.rpm",
          "flatpak-1.0.3-3.oe1.x86_64.rpm",
          "flatpak-devel-1.0.3-3.oe1.x86_64.rpm",
          "flatpak-debugsource-1.0.3-3.oe1.x86_64.rpm",
          "flatpak-debuginfo-1.0.3-3.oe1.x86_64.rpm",
          "flatpak-1.0.3-3.oe1.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:20.03-LTS",
        "name": "flatpak",
        "purl": "pkg:rpm/openEuler/flatpak\u0026distro=openEuler-20.03-LTS"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.0.3-3.oe1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "aarch64": [
          "flatpak-debugsource-1.0.3-3.oe1.aarch64.rpm",
          "flatpak-debuginfo-1.0.3-3.oe1.aarch64.rpm",
          "flatpak-devel-1.0.3-3.oe1.aarch64.rpm",
          "flatpak-1.0.3-3.oe1.aarch64.rpm"
        ],
        "noarch": [
          "flatpak-help-1.0.3-3.oe1.noarch.rpm"
        ],
        "src": [
          "flatpak-1.0.3-3.oe1.src.rpm"
        ],
        "x86_64": [
          "flatpak-devel-1.0.3-3.oe1.x86_64.rpm",
          "flatpak-debugsource-1.0.3-3.oe1.x86_64.rpm",
          "flatpak-debuginfo-1.0.3-3.oe1.x86_64.rpm",
          "flatpak-1.0.3-3.oe1.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:20.03-LTS-SP1",
        "name": "flatpak",
        "purl": "pkg:rpm/openEuler/flatpak\u0026distro=openEuler-20.03-LTS-SP1"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.0.3-3.oe1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "severity": "High"
  },
  "details": "flatpak is a system for building, distributing and running sandboxed desktop applications on Linux. See https://wiki.gnome.org/Projects/SandboxedApps for more information.\r\n\r\nSecurity Fix(es):\r\n\r\nFlatpak is a system for building, distributing, and running sandboxed desktop applications on Linux. A bug was discovered in the `flatpak-portal` service that can allow sandboxed applications to execute arbitrary code on the host system (a sandbox escape). This sandbox-escape bug is present in versions from 0.11.4 and before fixed versions 1.8.5 and 1.9.4. The Flatpak portal D-Bus service (`flatpak-portal`, also known by its D-Bus service name `org.freedesktop.portal.Flatpak`) allows apps in a Flatpak sandbox to launch their own subprocesses in a new sandbox instance, either with the same security settings as the caller or with more restrictive security settings. For example, this is used in Flatpak-packaged web browsers such as Chromium to launch subprocesses that will process untrusted web content, and give those subprocesses a more restrictive sandbox than the browser itself. In vulnerable versions, the Flatpak portal service passes caller-specified environment variables to non-sandboxed processes on the host system, and in particular to the `flatpak run` command that is used to launch the new sandbox instance. A malicious or compromised Flatpak app could set environment variables that are trusted by the `flatpak run` command, and use them to execute arbitrary code that is not in a sandbox. As a workaround, this vulnerability can be mitigated by preventing the `flatpak-portal` service from starting, but that mitigation will prevent many Flatpak apps from working correctly. This is fixed in versions 1.8.5 and 1.9.4.(CVE-2021-21261)",
  "id": "OESA-2021-1043",
  "modified": "2026-08-06T11:04:16Z",
  "published": "2021-03-05T11:04:16Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://openeuler.org/en/security/safety-bulletin/detail.html?id=openEuler-SA-2021-1043"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-21261"
    }
  ],
  "schema_version": "1.7.2",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "flatpak security update",
  "upstream": [
    "CVE-2021-21261"
  ]
}

CVE-2021-21261 (GCVE-0-2021-21261)

Vulnerability from cvelistv5 – Published: 2021-01-14 19:40 – Updated: 2024-08-03 18:09

Title

Flatpak sandbox escape via spawn portal

Summary

Flatpak is a system for building, distributing, and running sandboxed desktop applications on Linux. A bug was discovered in the `flatpak-portal` service that can allow sandboxed applications to execute arbitrary code on the host system (a sandbox escape). This sandbox-escape bug is present in versions from 0.11.4 and before fixed versions 1.8.5 and 1.10.0. The Flatpak portal D-Bus service (`flatpak-portal`, also known by its D-Bus service name `org.freedesktop.portal.Flatpak`) allows apps in a Flatpak sandbox to launch their own subprocesses in a new sandbox instance, either with the same security settings as the caller or with more restrictive security settings. For example, this is used in Flatpak-packaged web browsers such as Chromium to launch subprocesses that will process untrusted web content, and give those subprocesses a more restrictive sandbox than the browser itself. In vulnerable versions, the Flatpak portal service passes caller-specified environment variables to non-sandboxed processes on the host system, and in particular to the `flatpak run` command that is used to launch the new sandbox instance. A malicious or compromised Flatpak app could set environment variables that are trusted by the `flatpak run` command, and use them to execute arbitrary code that is not in a sandbox. As a workaround, this vulnerability can be mitigated by preventing the `flatpak-portal` service from starting, but that mitigation will prevent many Flatpak apps from working correctly. This is fixed in versions 1.8.5 and 1.10.0.

Severity

7.3 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N

CWE

CWE-74 - Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Assigner

GitHub_M mitre root

References

8 references

URL	Tags
https://github.com/flatpak/flatpak/security/advis…	x_refsource_CONFIRM
https://github.com/flatpak/flatpak/releases/tag/1.8.5	x_refsource_MISC
https://www.debian.org/security/2021/dsa-4830	vendor-advisoryx_refsource_DEBIAN
https://github.com/flatpak/flatpak/commit/6d1773d…	x_refsource_MISC
https://github.com/flatpak/flatpak/commit/6e5ae7a…	x_refsource_MISC
https://github.com/flatpak/flatpak/commit/aeb6a7a…	x_refsource_MISC
https://github.com/flatpak/flatpak/commit/cc14010…	x_refsource_MISC
https://security.gentoo.org/glsa/202101-21	vendor-advisoryx_refsource_GENTOO

Impacted products

1 product

Vendor	Product	Version
flatpak	flatpak	Affected: >= 0.11.4, < 1.8.5 Affected: >= 1.9.0, < 1.10.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-03T18:09:14.989Z",
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            ],
            "url": "https://github.com/flatpak/flatpak/security/advisories/GHSA-4ppf-fxf6-vxg2"
          },
          {
            "tags": [
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        ],
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    ],
    "cna": {
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        {
          "product": "flatpak",
          "vendor": "flatpak",
          "versions": [
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              "status": "affected",
              "version": "\u003e= 0.11.4, \u003c 1.8.5"
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        }
      ],
      "descriptions": [
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          "value": "Flatpak is a system for building, distributing, and running sandboxed desktop applications on Linux. A bug was discovered in the `flatpak-portal` service that can allow sandboxed applications to execute arbitrary code on the host system (a sandbox escape). This sandbox-escape bug is present in versions from 0.11.4 and before fixed versions 1.8.5 and 1.10.0. The Flatpak portal D-Bus service (`flatpak-portal`, also known by its D-Bus service name `org.freedesktop.portal.Flatpak`) allows apps in a Flatpak sandbox to launch their own subprocesses in a new sandbox instance, either with the same security settings as the caller or with more restrictive security settings. For example, this is used in Flatpak-packaged web browsers such as Chromium to launch subprocesses that will process untrusted web content, and give those subprocesses a more restrictive sandbox than the browser itself. In vulnerable versions, the Flatpak portal service passes caller-specified environment variables to non-sandboxed processes on the host system, and in particular to the `flatpak run` command that is used to launch the new sandbox instance. A malicious or compromised Flatpak app could set environment variables that are trusted by the `flatpak run` command, and use them to execute arbitrary code that is not in a sandbox. As a workaround, this vulnerability can be mitigated by preventing the `flatpak-portal` service from starting, but that mitigation will prevent many Flatpak apps from working correctly. This is fixed in versions 1.8.5 and 1.10.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "NONE",
            "baseScore": 7.3,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
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            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N",
            "version": "3.1"
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        }
      ],
      "problemTypes": [
        {
          "descriptions": [
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      },
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        },
        {
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          "url": "https://github.com/flatpak/flatpak/commit/6e5ae7a109cdfa9735ea7ccbd8cb79f9e8d3ae8b"
        },
        {
          "tags": [
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          "url": "https://github.com/flatpak/flatpak/commit/aeb6a7ab0abaac4a8f4ad98b3df476d9de6b8bd4"
        },
        {
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          "url": "https://github.com/flatpak/flatpak/commit/cc1401043c075268ecc652eac557ef8076b5eaba"
        },
        {
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          "tags": [
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      ],
      "source": {
        "advisory": "GHSA-4ppf-fxf6-vxg2",
        "discovery": "UNKNOWN"
      },
      "title": "Flatpak sandbox escape via spawn portal",
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                      "version": {
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                            "version_value": "\u003e= 0.11.4, \u003c 1.8.5"
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        "impact": {
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              "name": "https://github.com/flatpak/flatpak/commit/cc1401043c075268ecc652eac557ef8076b5eaba",
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              "url": "https://github.com/flatpak/flatpak/commit/cc1401043c075268ecc652eac557ef8076b5eaba"
            },
            {
              "name": "GLSA-202101-21",
              "refsource": "GENTOO",
              "url": "https://security.gentoo.org/glsa/202101-21"
            }
          ]
        },
        "source": {
          "advisory": "GHSA-4ppf-fxf6-vxg2",
          "discovery": "UNKNOWN"
        }
      }
    }
  },
  "cveMetadata": {
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    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2021-21261",
    "datePublished": "2021-01-14T19:40:21.000Z",
    "dateReserved": "2020-12-22T00:00:00.000Z",
    "dateUpdated": "2024-08-03T18:09:14.989Z",
    "state": "PUBLISHED"
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  "dataType": "CVE_RECORD",
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}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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.