Flatpak: flatpak: world-writable temporary child repositories in system-helper cache path

{
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "cveMetadata": {
    "cveId": "CVE-2026-97026",
    "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
    "assignerShortName": "redhat",
    "dateUpdated": "2026-09-28T20:57:03.702Z",
    "dateReserved": "2026-09-23T21:11:59.431Z",
    "datePublished": "2026-09-28T20:57:03.702Z",
    "state": "PUBLISHED"
  },
  "containers": {
    "cna": {
      "providerMetadata": {
        "orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
        "shortName": "redhat",
        "dateUpdated": "2026-09-28T20:57:03.702Z"
      },
      "datePublic": "2026-09-28T13:28:31.000Z",
      "title": "Flatpak: flatpak: world-writable temporary child repositories in system-helper cache path",
      "descriptions": [
        {
          "lang": "en",
          "value": "Flatpak creates temporary child repository directories under the user cache with world-writable permissions (0777). On multi-user systems with a permissive umask, other local users could read or modify the temporary directory used while installing apps or runtimes, potentially causing installation failures (denial of service); tampered content would fail signature/digest verification rather than being trusted."
        }
      ],
      "affected": [
        {
          "vendor": "Red Hat",
          "product": "Red Hat Enterprise Linux 10",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "packageName": "flatpak",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:10"
          ],
          "defaultStatus": "affected"
        },
        {
          "vendor": "Red Hat",
          "product": "Red Hat Enterprise Linux 7",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "packageName": "flatpak",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:7"
          ],
          "defaultStatus": "affected"
        },
        {
          "vendor": "Red Hat",
          "product": "Red Hat Enterprise Linux 8",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "packageName": "flatpak",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:8"
          ],
          "defaultStatus": "affected"
        },
        {
          "vendor": "Red Hat",
          "product": "Red Hat Enterprise Linux 9",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "packageName": "flatpak",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:9"
          ],
          "defaultStatus": "affected"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "lang": "en",
              "description": "Creation of Temporary File With Insecure Permissions",
              "cweId": "CWE-378",
              "type": "CWE"
            }
          ]
        }
      ],
      "references": [
        {
          "url": "https://access.redhat.com/security/cve/CVE-2026-97026",
          "tags": [
            "vdb-entry",
            "x_refsource_REDHAT"
          ]
        },
        {
          "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2542637",
          "name": "RHBZ#2542637",
          "tags": [
            "issue-tracking",
            "x_refsource_REDHAT"
          ]
        },
        {
          "url": "https://github.com/flatpak/flatpak/security/advisories/GHSA-r9w3-qx54-qvc8"
        }
      ],
      "metrics": [
        {},
        {
          "format": "CVSS",
          "cvssV3_1": {
            "version": "3.1",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:L",
            "attackVector": "LOCAL",
            "attackComplexity": "LOW",
            "privilegesRequired": "LOW",
            "userInteraction": "REQUIRED",
            "scope": "UNCHANGED",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "availabilityImpact": "LOW",
            "baseScore": 3.9,
            "baseSeverity": "LOW"
          }
        }
      ],
      "workarounds": [
        {
          "lang": "en",
          "value": "Set a umask that does not allow other users to write to the cache directory, for example: umask 022.\n\nNote that a umask that does not allow read/exec access by all (for example 027 or 077) will prevent the flatpak-system-helper from reading the temporary directory directly, resulting in falling back to copying the repository inefficiently, with a warning."
        }
      ],
      "timeline": [
        {
          "time": "2026-09-28T13:28:31.000Z",
          "lang": "en",
          "value": "Reported to Red Hat."
        },
        {
          "time": "2026-09-28T13:28:31.000Z",
          "lang": "en",
          "value": "Made public."
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Red Hat would like to thank AISLE for reporting this issue."
        }
      ]
    }
  }
}