{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/OliveTin/OliveTin"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.0.0-20260531214440-ebffd9f040f7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-53541"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-20"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-24T17:43:50Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Description\n\nThe `filterToDefinedArgumentsOnly` function in the executor is intended to discard any arguments not explicitly defined in the action\u0027s configuration. However, a special case allows any argument whose name starts with `ot_` to bypass this filter. While two system arguments (`ot_executionTrackingId` and `ot_username`) are injected by OliveTin and overridden, all other `ot_`-prefixed arguments supplied by the user pass through unmodified.\n\nThese bypassed arguments are:\n\n1. **Not type-checked** \u2014 the validation loop only iterates over the action\u0027s defined arguments, so `ot_`-prefixed arguments skip all type safety checks entirely.\n2. **Set as environment variables** \u2014 via `buildEnv()`, with completely unvalidated values, and passed to the executed command.\n3. **Included in the template context** \u2014 available as `.Arguments.ot_*` in template rendering.\n\n### Affected Code\n\n**Filter bypass \u2014 `service/internal/executor/executor.go` (lines 728\u2013731):**\n\n```go\nfunc keepArgument(name string, definedNames map[string]struct{}) bool {\n    _, ok := definedNames[name]\n    return ok || strings.HasPrefix(name, \"ot_\")\n}\n```\n\n**System args only override two keys \u2014 `service/internal/executor/executor.go` (lines 742\u2013745):**\n\n```go\nfunc injectSystemArgs(req *ExecutionRequest) {\n    req.Arguments[\"ot_executionTrackingId\"] = req.TrackingID\n    req.Arguments[\"ot_username\"] = req.AuthenticatedUser.Username\n}\n```\n\nAny other `ot_`-prefixed argument (e.g., `ot_malicious`) survives both functions.\n\n**Unvalidated values become environment variables \u2014 `service/internal/executor/executor.go` (lines 867\u2013882):**\n\n```go\nfunc buildEnv(args map[string]string) []string {\n    ret := append(os.Environ(), \"OLIVETIN=1\")\n    for k, v := range args {\n        varName := fmt.Sprintf(\"%v\", strings.TrimSpace(strings.ToUpper(k)))\n        if varName == \"\" { continue }\n        ret = append(ret, fmt.Sprintf(\"%v=%v\", varName, v))\n    }\n    return ret\n}\n```\n\nThe value `v` is never validated. It can contain newlines, shell metacharacters, null bytes, or any arbitrary data.\n\n### Proof of Concept\n\nAn attacker sends a `StartAction` request with extra `ot_`-prefixed arguments:\n\n```json\n{\n  \"bindingId\": \"\u003cany-action-id\u003e\",\n  \"arguments\": [\n    { \"name\": \"ot_custom_var\", \"value\": \"arbitrary unvalidated content \\n with newlines\" },\n    { \"name\": \"ot_another\",    \"value\": \"$(whoami)\" }\n  ]\n}\n```\n\nThese arguments:\n\n- Pass through `filterToDefinedArgumentsOnly` (the `ot_` prefix exempts them).\n- Are never type-checked (not in the action\u0027s argument definitions).\n- Become environment variables `OT_CUSTOM_VAR` and `OT_ANOTHER` in the executed command\u0027s environment.\n- Are available in the template rendering context as `.Arguments.ot_custom_var` and `.Arguments.ot_another`.\n\n### Impact\n\n- **Environment variable pollution** \u2014 attacker can set arbitrary environment variables (with `OT_` uppercased prefix) in the execution environment of any action they can trigger. Scripts or programs that read custom environment variables could be influenced.\n- **Potential for secondary exploitation** \u2014 if any executed script or command reads `OT_`-prefixed environment variables, the unvalidated content could cause unexpected behavior.\n- **Template context pollution** \u2014 although Go\u0027s `text/template` does not recursively evaluate data values (mitigating direct template injection), the extra arguments are accessible in the template context and could interact unexpectedly with custom template logic.\n\n### Suggested Fix\n\nRemove the `ot_` prefix exception from `keepArgument`, or restrict it to only the two known system arguments:\n\n```go\nvar systemArgs = map[string]struct{}{\n    \"ot_executionTrackingId\": {},\n    \"ot_username\":            {},\n}\n\nfunc keepArgument(name string, definedNames map[string]struct{}) bool {\n    _, isDefined := definedNames[name]\n    _, isSystem := systemArgs[name]\n    return isDefined || isSystem\n}\n```\n\n---\n\n## Discovery Methodology\n\nBoth vulnerabilities were identified through manual source code review of the OliveTin repository, focusing on:\n\n- Input validation boundaries (API request fields flowing into file system operations and execution contexts)\n- Argument filtering and type-checking logic in the executor\n- File path construction in the log persistence feature\n\nNo automated scanners or fuzzing tools were used. The review was conducted against the current `main` branch source code.\n\n---",
  "id": "GHSA-prj9-97mp-mwh2",
  "modified": "2026-06-24T17:43:50Z",
  "published": "2026-06-24T17:43:50Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/OliveTin/OliveTin/security/advisories/GHSA-prj9-97mp-mwh2"
    },
    {
      "type": "WEB",
      "url": "https://github.com/OliveTin/OliveTin/commit/ebffd9f040f791208aee1db2e5a8aecd1e3e603d"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/OliveTin/OliveTin"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "OliveTin has Unvalidated `ot_`-prefixed Arguments that Bypass Input Filtering"
}