Vulnerability-Lookup

ubuntu-cve-2026-90616

Vulnerability from osv_ubuntu

Published

2026-09-14 00:00

Modified

2026-09-14 00:00

Summary

Details

In Flatpak before 1.18.1, a malicious sandboxed app can obtain arbitrary read and write access to files on the host, which can be escalated to arbitrary code execution on the host, a different vulnerability than CVE-2026-76925. Flatpak creates a few app data directories (e.g., /var/cache, /var/data, /var/config, and /var/tmp) in every sandbox on every app launch where, in some cases, components of the path are attacker-controlled. Missing symlink protection can redirect the directories. Some of these directories are bind-mounted by Flatpak by passing the path (e.g., /home/user/.var/app/APP_ID/cache/tmp), which contains attacker-controlled directories (tmp) to bwrap --bind SRC DST. bwrap passes the path on to the kernel, which then follows symlinks. A malicious symlink can point to arbitrary locations on the host and it will become mounted inside the sandbox.

Severity

7.4 (High)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-90616	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-90616	REPORT
	https://github.com/flatpak/flatpak/security/advis…	REPORT
	https://www.openwall.com/lists/oss-security/2026/…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "flatpak",
            "binary_version": "1.0.9-0ubuntu0.4+esm1"
          },
          {
            "binary_name": "flatpak-tests",
            "binary_version": "1.0.9-0ubuntu0.4+esm1"
          },
          {
            "binary_name": "gir1.2-flatpak-1.0",
            "binary_version": "1.0.9-0ubuntu0.4+esm1"
          },
          {
            "binary_name": "libflatpak0",
            "binary_version": "1.0.9-0ubuntu0.4+esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "flatpak",
        "purl": "pkg:deb/ubuntu/flatpak@1.0.9-0ubuntu0.4+esm1?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.8.7-5",
        "0.10.0-1",
        "0.10.0-2",
        "0.10.1-1",
        "0.10.2-1",
        "0.10.2.1-1",
        "0.10.2.1-2",
        "0.10.3-1",
        "0.11.1-0ubuntu1",
        "0.11.3-2",
        "0.11.3-3",
        "0.11.7-0ubuntu0.1",
        "1.0.1-0ubuntu0.1",
        "1.0.6-0ubuntu0.1",
        "1.0.7-0ubuntu0.18.04.1",
        "1.0.8-0ubuntu0.18.04.1",
        "1.0.9-0ubuntu0.1",
        "1.0.9-0ubuntu0.2",
        "1.0.9-0ubuntu0.3",
        "1.0.9-0ubuntu0.4",
        "1.0.9-0ubuntu0.4+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "flatpak",
            "binary_version": "1.6.5-0ubuntu0.5+esm1"
          },
          {
            "binary_name": "flatpak-tests",
            "binary_version": "1.6.5-0ubuntu0.5+esm1"
          },
          {
            "binary_name": "gir1.2-flatpak-1.0",
            "binary_version": "1.6.5-0ubuntu0.5+esm1"
          },
          {
            "binary_name": "libflatpak0",
            "binary_version": "1.6.5-0ubuntu0.5+esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "flatpak",
        "purl": "pkg:deb/ubuntu/flatpak@1.6.5-0ubuntu0.5+esm1?arch=source\u0026distro=esm-apps/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.4.3-1",
        "1.6.0-1",
        "1.6.1-1",
        "1.6.2-1",
        "1.6.3-1",
        "1.6.5-0ubuntu0.1",
        "1.6.5-0ubuntu0.2",
        "1.6.5-0ubuntu0.3",
        "1.6.5-0ubuntu0.4",
        "1.6.5-0ubuntu0.5",
        "1.6.5-0ubuntu0.5+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "flatpak",
            "binary_version": "1.12.7-1ubuntu0.1+esm1"
          },
          {
            "binary_name": "flatpak-tests",
            "binary_version": "1.12.7-1ubuntu0.1+esm1"
          },
          {
            "binary_name": "gir1.2-flatpak-1.0",
            "binary_version": "1.12.7-1ubuntu0.1+esm1"
          },
          {
            "binary_name": "libflatpak0",
            "binary_version": "1.12.7-1ubuntu0.1+esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:22.04:LTS",
        "name": "flatpak",
        "purl": "pkg:deb/ubuntu/flatpak@1.12.7-1ubuntu0.1+esm1?arch=source\u0026distro=esm-apps/jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.10.2-3",
        "1.12.2-1",
        "1.12.2-2",
        "1.12.3-1",
        "1.12.4-1",
        "1.12.5-1",
        "1.12.6-1",
        "1.12.7-1",
        "1.12.7-1ubuntu0.1",
        "1.12.7-1ubuntu0.1+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "flatpak",
            "binary_version": "1.14.6-1ubuntu0.1+esm1"
          },
          {
            "binary_name": "flatpak-tests",
            "binary_version": "1.14.6-1ubuntu0.1+esm1"
          },
          {
            "binary_name": "gir1.2-flatpak-1.0",
            "binary_version": "1.14.6-1ubuntu0.1+esm1"
          },
          {
            "binary_name": "libflatpak0",
            "binary_version": "1.14.6-1ubuntu0.1+esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:24.04:LTS",
        "name": "flatpak",
        "purl": "pkg:deb/ubuntu/flatpak@1.14.6-1ubuntu0.1+esm1?arch=source\u0026distro=esm-apps/noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.14.4-2",
        "1.14.5-1",
        "1.14.5-1build1",
        "1.14.5-1build4",
        "1.14.5-1build5",
        "1.14.5-1build6",
        "1.14.6-1",
        "1.14.6-1ubuntu0.1",
        "1.14.6-1ubuntu0.1+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "flatpak",
            "binary_version": "1.16.6-1"
          },
          {
            "binary_name": "flatpak-tests",
            "binary_version": "1.16.6-1"
          },
          {
            "binary_name": "gir1.2-flatpak-1.0",
            "binary_version": "1.16.6-1"
          },
          {
            "binary_name": "libflatpak0",
            "binary_version": "1.16.6-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "flatpak",
        "purl": "pkg:deb/ubuntu/flatpak@1.16.6-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.16.1-2ubuntu1",
        "1.16.1-3ubuntu1",
        "1.16.2-1",
        "1.16.3-1",
        "1.16.3-1build1",
        "1.16.4-1",
        "1.16.4-2",
        "1.16.6-1"
      ]
    }
  ],
  "aliases": [],
  "details": "In Flatpak before 1.18.1, a malicious sandboxed app can obtain arbitrary read and write access to files on the host, which can be escalated to arbitrary code execution on the host, a different vulnerability than CVE-2026-76925. Flatpak creates a few app data directories (e.g., /var/cache, /var/data, /var/config, and /var/tmp) in every sandbox on every app launch where, in some cases, components of the path are attacker-controlled. Missing symlink protection can redirect the directories. Some of these directories are bind-mounted by Flatpak by passing the path (e.g., /home/user/.var/app/APP_ID/cache/tmp), which contains attacker-controlled directories (tmp) to bwrap --bind SRC DST. bwrap passes the path on to the kernel, which then follows symlinks. A malicious symlink can point to arbitrary locations on the host and it will become mounted inside the sandbox.",
  "id": "UBUNTU-CVE-2026-90616",
  "modified": "2026-09-14T00:00:00Z",
  "published": "2026-09-14T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-90616"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-90616"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/flatpak/flatpak/security/advisories/GHSA-8688-9x26-hhxj"
    },
    {
      "type": "REPORT",
      "url": "https://www.openwall.com/lists/oss-security/2026/08/11/9"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-90616"
  ]
}

CVE-2026-90616 (GCVE-0-2026-90616)

Vulnerability from cvelistv5 – Published: 2026-09-12 20:00 – Updated: 2026-09-12 20:00

Summary

Severity

7.4 (High)


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

CWE

CWE-61 - UNIX Symbolic Link (Symlink) Following

Assigner

mitre mitre root

References

2 references

URL	Tags
https://github.com/flatpak/flatpak/security/advis…
https://www.openwall.com/lists/oss-security/2026/…

Impacted products

1 product

Vendor	Product	Version
Flatpak	Flatpak	Affected: 0 , < 1.18.1 (semver) cpe:2.3:a:flatpak:flatpak::::::::

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "platforms": [
            "Linux"
          ],
          "product": "Flatpak",
          "repo": "https://github.com/flatpak/flatpak",
          "vendor": "Flatpak",
          "versions": [
            {
              "lessThan": "1.18.1",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:flatpak:flatpak:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "1.18.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In Flatpak before 1.18.1, a malicious sandboxed app can obtain arbitrary read and write access to files on the host, which can be escalated to arbitrary code execution on the host, a different vulnerability than CVE-2026-76925. Flatpak creates a few app data directories (e.g., /var/cache, /var/data, /var/config, and /var/tmp) in every sandbox on every app launch where, in some cases, components of the path are attacker-controlled. Missing symlink protection can redirect the directories. Some of these directories are bind-mounted by Flatpak by passing the path (e.g., /home/user/.var/app/APP_ID/cache/tmp), which contains attacker-controlled directories (tmp) to bwrap --bind SRC DST. bwrap passes the path on to the kernel, which then follows symlinks. A malicious symlink can point to arbitrary locations on the host and it will become mounted inside the sandbox."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 7.4,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-61",
              "description": "CWE-61 UNIX Symbolic Link (Symlink) Following",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-12T20:00:58.476Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "url": "https://github.com/flatpak/flatpak/security/advisories/GHSA-8688-9x26-hhxj"
        },
        {
          "url": "https://www.openwall.com/lists/oss-security/2026/08/11/9"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003ca target=\"_blank\" rel=\"noopener noreferrer\" href=\"https://github.com/flatpak/flatpak/commit/478072972056d2d15c768c246f80abdf83cf0e5e\"\u003ehttps://github.com/flatpak/flatpak/commit/478072972056d2d15c768c246f80abdf83cf0e5e\u003c/a\u003e\u003cbr\u003e"
            }
          ],
          "value": "https://github.com/flatpak/flatpak/commit/478072972056d2d15c768c246f80abdf83cf0e5e"
        }
      ],
      "x_generator": {
        "engine": "CVE-Request-form 0.0.1"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2026-90616",
    "datePublished": "2026-09-12T20:00:58.476Z",
    "dateReserved": "2026-09-12T20:00:58.046Z",
    "dateUpdated": "2026-09-12T20:00:58.476Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.