CVE-2026-102925: Virtualenv Virtualenv Bash And Fish Activation Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-p58f-9548-mpm2",
  "modified" : "2026-10-01T15:09:18Z",
  "published" : "2026-10-01T15:09:17Z",
  "aliases" : [ "CVE-2026-102925" ],
  "summary" : "virtualenv bash and fish activation scripts execute commands embedded in paths",
  "details" : "### Impact\n\nThe generated `activate` (bash/zsh) and `activate.fish` scripts interpolate a `shlex.quote`-ed value into a position that quotes it a second time. The extra quotes terminate the quoted run early and leave part of the value parsed as shell code, so a path containing shell metacharacters runs commands when a user sources the activation script.\n\n`activate` is affected through the virtual environment's own path, on the branch that reports a relocated environment:\n\n```sh\necho \"Virtual environment directory __VIRTUAL_ENV__ does not exist!\" >&2\n```\n\nFor a destination named `x'$(id)'y`, `shlex.quote` emits `'x'\"'\"'$(id)'\"'\"'y'`. The inner `\"` closes the enclosing double quote and `$(id)` is left unquoted. Backtick and `;` payloads reach the same result. This branch runs whenever the recorded path is absent, which is the normal case for a virtual environment copied or distributed to another machine.\n\n`activate.fish` is affected through the interpreter's Tcl/Tk library paths:\n\n```fish\nset -gx TCL_LIBRARY '__TCL_LIBRARY__'\n```\n\n`shlex.quote` already returns `'/tcl/(cmd)/lib'`, so the rendered line is `''/tcl/(cmd)/lib''`. fish concatenates the adjacent quoted runs and expands the `(cmd)` left between them. The same doubling also splits a path containing a space into two list elements, corrupting `TCL_LIBRARY` and `TK_LIBRARY`.\n\nThis is the same defect class as GHSA-x78j-v8h9-3j2q, which covered `activate.bat`.\n\n### Patches\n\nFixed in 21.7.13 by moving the placeholders outside the surrounding quotes, so each value keeps only the quoting `shlex.quote` applied. Fix: https://github.com/pypa/virtualenv/pull/3252\n\n### Workarounds\n\nAvoid creating or distributing virtual environments whose path contains `'`, `` ` ``, `$`, `;`, `(` or `)`, and inspect the generated activation script before sourcing one you did not create.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "virtualenv"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "21.7.13"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 21.7.12"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/pypa/virtualenv/security/advisories/GHSA-p58f-9548-mpm2"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-102925"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/virtualenv/pull/3252"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/virtualenv/commit/4d5a105ec2a2723b8c7f4571bb68f4f71d01e3f6"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/virtualenv/PYSEC-2026-4013.yaml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/pypa/virtualenv"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/virtualenv/releases/tag/21.7.13"
  }, {
    "type" : "WEB",
    "url" : "https://pypi.org/project/virtualenv"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-78" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-10-01T15:09:17Z",
    "nvd_published_at" : "2026-09-29T21:17:18Z"
  }
}