CVE-2026-50568: Fission SanitizeFilePath Lexical HasPrefix Bypass Permits Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-r5jh-q2mw-gcx4",
  "modified" : "2026-07-28T20:18:30Z",
  "published" : "2026-07-28T20:18:30Z",
  "aliases" : [ "CVE-2026-50568" ],
  "summary" : "Fission: SanitizeFilePath lexical HasPrefix bypass permits sibling-directory escape",
  "details" : "`SanitizeFilePath` in `pkg/utils/utils.go` validated that a path stayed under a safe directory by calling `strings.HasPrefix(path, safedir)`. This is a lexical check, not a directory boundary check: `/packages-extra/evil` starts with\n`/packages`, so it passed. The function did not enforce a path-separator boundary, so any sibling directory whose name began with the safe-directory string was accepted.\n\nCallers included the builder's `Clean` handler (`pkg/builder/builder.go:208`) and the fetcher's `Fetch` / `Upload` handlers (`pkg/fetcher/fetcher.go`). A tenant who could pre-create or control a sibling directory under the fetcher /\nbuilder's shared volume could induce a write or read outside the intended safe directory.\n\n### Affected\n\n- Project: `github.com/fission/fission`\n- Versions: all versions through v1.24.0 with `SanitizeFilePath` in the tree\n- Audited commit: `647c141`\n- Component: `pkg/utils/utils.go:SanitizeFilePath`\n- Callers: `pkg/builder/builder.go:157,164,208`, `pkg/fetcher/fetcher.go:296,311,450,496,565,571`\n- Configuration: default; requires a sibling directory to the safe dir to exist on the filesystem\n\n\nFix section (paste into the Fix / Patches field)\n\nFixed in [v1.25.0](https://github.com/fission/fission/releases/tag/v1.25.0) by:\n\n- [PR #3445](https://github.com/fission/fission/pull/3445) (commit [`8298e33e`](https://github.com/fission/fission/commit/8298e33ea7457702f893eae11077987cf905edb4)) — migrate every `SanitizeFilePath` call site (fetcher: `storePath` /\n`tmpPath` / `secretDir` / `configDir` / rename + `writeSecretOrConfigMap`; builder: `srcPkg` / `deployPkg` path validation and `srcPkg` stat) to new `pkg/utils/root.go` helpers (`RootJoin`, `RootStat`, `RootWriteFile`, `RootMkdirAll`,\n`RootRename`) that operate through `os.Root`. `os.Root` enforces directory confinement in the kernel and is recognized by CodeQL `go/path-injection` as a traversal barrier.\n- [PR #3446](https://github.com/fission/fission/pull/3446) (commit [`5aac6f0b`](https://github.com/fission/fission/commit/5aac6f0bcdf840e28f3f06c846ca7ae1866b3957)) — delete the deprecated `SanitizeFilePath` itself once no callers\nremained. The vulnerable function no longer exists in the tree.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/fission/fission"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.25.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.24.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/security/advisories/GHSA-r5jh-q2mw-gcx4"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-50568"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/pull/3445"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/pull/3446"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/commit/5aac6f0bcdf840e28f3f06c846ca7ae1866b3957"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/commit/8298e33ea7457702f893eae11077987cf905edb4"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/fission/fission"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/releases/tag/v1.25.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-41" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-28T20:18:30Z",
    "nvd_published_at" : "2026-06-10T18:17:13Z"
  }
}