CVE-2026-27602: Modoboa Modoboa Has OS Command Injection Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-wwv8-cqpr-vx3m",
  "modified" : "2026-03-27T22:08:53Z",
  "published" : "2026-03-25T17:03:37Z",
  "aliases" : [ "CVE-2026-27602" ],
  "summary" : "Modoboa has OS Command Injection",
  "details" : "### Summary\n\n`exec_cmd()` in `modoboa/lib/sysutils.py` always runs subprocess calls with `shell=True`. Since domain names flow directly into shell command strings without any sanitization, a Reseller or SuperAdmin can include shell metacharacters in a domain name to run arbitrary OS commands on the server.\n\n### Details\n\nThe root cause is in `modoboa/lib/sysutils.py:31`:\n\n```python\nkwargs[\"shell\"] = True\nprocess = subprocess.Popen(cmd, **kwargs)\n```\n\nWhen a create a domain is created with DKIM enabled, the domain name gets embedded into a shell command like this:\n\n```python\nexec_cmd(f\"openssl genrsa -out {dkim_storage_dir}/{domain.name}.pem {key_size}\")\n```\n\nIf the domain name contains something like `$(id>/tmp/proof).example.com`, the shell executes the injected command before running openssl.\n\nThe same pattern appears in several other places:\n\n- `modoboa/admin/jobs.py:38` — mailbox rename via `mv` using `full_address`\n- `modoboa/amavis/lib.py:202` — `sa-learn` using `domain.name`\n- `modoboa/admin/models/mailbox.py:150` — `doveadm user` using `full_address`\n- `modoboa/maillog/graphics.py:105–107` — `rrdtool` using `domain.name`\n- `modoboa/webmail/models.py:54–57` — `doveadm move/delete` using `account.email`\n\n### PoC\n\n1. Deploy modoboa <= 2.7.0\n2. Log in as a Reseller or SuperAdmin\n3. Create a new domain named `$(id>/tmp/proof).example.com` with DKIM enabled\n4. SSH into the server and read `/tmp/proof`\n\nSomething like this will be displayed:\n\n```\nuid=0(root) gid=0(root) groups=0(root)\n```\n\nConfirmed on commit b521bcb4f (latest main at time of discovery).\n\n### Impact\n\nAn attacker with Reseller-level access (or higher) can execute arbitrary OS commands on the mail server — in a typical Modoboa deployment this means running as root. All six identified sinks are reachable through normal application workflows.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "modoboa"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.7.1"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.7.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/modoboa/modoboa/security/advisories/GHSA-wwv8-cqpr-vx3m"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-27602"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/modoboa/modoboa/commit/27a7aa133d3608fe8c25ae39125d1012c333cbfa"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/modoboa/modoboa"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/modoboa/modoboa/releases/tag/2.7.1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-78" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-25T17:03:37Z",
    "nvd_published_at" : "2026-03-25T19:16:48Z"
  }
}