Vulnerability-Lookup

PYSEC-2026-4014

Vulnerability from pysec - Published: 2026-09-18 01:41 - Updated: 2026-09-30 16:13

Details

BatchActivator.quote() returned its input unchanged, the only activator with no escaping at all. --prompt, the VIRTUALENV_PROMPT environment variable, and the config file all set the prompt, and activate.bat writes it straight into @set "VAR=value". A prompt containing a double quote closes that string early, and whatever follows runs as live cmd.exe syntax. For example, a venv created with --prompt 'x" & calc & "' runs calc the moment someone runs activate.bat.

Anyone who templates a prompt from untrusted input (a CI job using a branch name, a wrapper script deriving an environment name from user input) hands an attacker code execution in the shell of anyone who activates the resulting venv on Windows.

Fixed in 21.7.12 by escaping the characters cmd.exe treats as live syntax inside this construct.

Impacted products

Name	purl
virtualenv	pkg:pypi/virtualenv

Aliases

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "virtualenv",
        "purl": "pkg:pypi/virtualenv"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "21.7.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.8",
        "0.8.1",
        "0.8.2",
        "0.8.3",
        "0.8.4",
        "0.9",
        "0.9.1",
        "0.9.2",
        "1.0",
        "1.1",
        "1.10",
        "1.10.1",
        "1.11",
        "1.11.1",
        "1.11.2",
        "1.11.3",
        "1.11.4",
        "1.11.5",
        "1.11.6",
        "1.2",
        "1.3",
        "1.3.1",
        "1.3.2",
        "1.3.3",
        "1.3.4",
        "1.4",
        "1.4.1",
        "1.4.2",
        "1.4.3",
        "1.4.4",
        "1.4.5",
        "1.4.6",
        "1.4.7",
        "1.4.8",
        "1.4.9",
        "1.4rc1",
        "1.5",
        "1.5.1",
        "1.5.2",
        "1.6",
        "1.6.1",
        "1.6.2",
        "1.6.3",
        "1.6.4",
        "1.7",
        "1.7.1",
        "1.7.1.1",
        "1.7.1.2",
        "1.7.2",
        "1.8",
        "1.8.1",
        "1.8.2",
        "1.8.3",
        "1.8.4",
        "1.9",
        "1.9.1",
        "12.0",
        "12.0.1",
        "12.0.2",
        "12.0.4",
        "12.0.5",
        "12.0.6",
        "12.0.7",
        "12.1.0",
        "12.1.1",
        "13.0.0",
        "13.0.1",
        "13.0.2",
        "13.0.3",
        "13.1.0",
        "13.1.1",
        "13.1.2",
        "14.0.0",
        "14.0.1",
        "14.0.2",
        "14.0.3",
        "14.0.4",
        "14.0.5",
        "14.0.6",
        "15.0.0",
        "15.0.1",
        "15.0.2",
        "15.0.3",
        "15.1.0",
        "15.2.0",
        "16.0.0",
        "16.1.0",
        "16.2.0",
        "16.3.0",
        "16.3.1.dev0",
        "16.4.0",
        "16.4.1",
        "16.4.3",
        "16.4.4.dev0",
        "16.5.0",
        "16.6.0",
        "16.6.1",
        "16.6.2",
        "16.7.0",
        "16.7.1",
        "16.7.10",
        "16.7.11",
        "16.7.12",
        "16.7.2",
        "16.7.3",
        "16.7.4",
        "16.7.5",
        "16.7.6",
        "16.7.7",
        "16.7.8",
        "16.7.9",
        "20.0.0",
        "20.0.0b1",
        "20.0.0b2",
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        "20.0.10",
        "20.0.11",
        "20.0.12",
        "20.0.13",
        "20.0.14",
        "20.0.15",
        "20.0.16",
        "20.0.17",
        "20.0.18",
        "20.0.19",
        "20.0.2",
        "20.0.20",
        "20.0.21",
        "20.0.22",
        "20.0.23",
        "20.0.24",
        "20.0.25",
        "20.0.26",
        "20.0.27",
        "20.0.28",
        "20.0.29",
        "20.0.3",
        "20.0.30",
        "20.0.31",
        "20.0.32",
        "20.0.33",
        "20.0.34",
        "20.0.35",
        "20.0.4",
        "20.0.5",
        "20.0.6",
        "20.0.7",
        "20.0.8",
        "20.0.9",
        "20.1.0",
        "20.10.0",
        "20.11.0",
        "20.11.1",
        "20.11.2",
        "20.12.0",
        "20.12.1",
        "20.13.0",
        "20.13.1",
        "20.13.2",
        "20.13.3",
        "20.13.4",
        "20.14.0",
        "20.14.1",
        "20.15.0",
        "20.15.1",
        "20.16.0",
        "20.16.1",
        "20.16.2",
        "20.16.3",
        "20.16.4",
        "20.16.5",
        "20.16.6",
        "20.16.7",
        "20.17.0",
        "20.17.1",
        "20.18.0",
        "20.19.0",
        "20.2.0",
        "20.2.1",
        "20.2.2",
        "20.20.0",
        "20.21.0",
        "20.21.1",
        "20.22.0",
        "20.23.0",
        "20.23.1",
        "20.24.0",
        "20.24.1",
        "20.24.2",
        "20.24.3",
        "20.24.4",
        "20.24.5",
        "20.24.6",
        "20.24.7",
        "20.25.0",
        "20.25.1",
        "20.25.2",
        "20.25.3",
        "20.26.0",
        "20.26.1",
        "20.26.2",
        "20.26.3",
        "20.26.4",
        "20.26.5",
        "20.26.6",
        "20.27.0",
        "20.27.1",
        "20.28.0",
        "20.28.1",
        "20.29.0",
        "20.29.1",
        "20.29.2",
        "20.29.3",
        "20.3.0",
        "20.3.1",
        "20.30.0",
        "20.31.0",
        "20.31.1",
        "20.31.2",
        "20.32.0",
        "20.33.0",
        "20.33.1",
        "20.34.0",
        "20.35.0",
        "20.35.1",
        "20.35.2",
        "20.35.3",
        "20.35.4",
        "20.36.0",
        "20.36.1",
        "20.38.0",
        "20.39.0",
        "20.39.1",
        "20.4.0",
        "20.4.1",
        "20.4.2",
        "20.4.3",
        "20.4.4",
        "20.4.5",
        "20.4.6",
        "20.4.7",
        "20.5.0",
        "20.6.0",
        "20.7.0",
        "20.7.1",
        "20.7.2",
        "20.8.0",
        "20.8.1",
        "20.9.0",
        "21.0.0",
        "21.1.0",
        "21.2.0",
        "21.2.1",
        "21.2.2",
        "21.2.3",
        "21.2.4",
        "21.3.0",
        "21.3.1",
        "21.3.2",
        "21.3.3",
        "21.4.0",
        "21.4.1",
        "21.4.2",
        "21.4.3",
        "21.5.0",
        "21.5.1",
        "21.5.2",
        "21.6.0",
        "21.6.1",
        "21.7.0",
        "21.7.1",
        "21.7.10",
        "21.7.11",
        "21.7.2",
        "21.7.3",
        "21.7.4",
        "21.7.5",
        "21.7.6",
        "21.7.7",
        "21.7.8",
        "21.7.9"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-102937",
    "GHSA-x78j-v8h9-3j2q"
  ],
  "credits": [
    {
      "name": "Bern\u00e1t G\u00e1bor",
      "type": "FINDER"
    }
  ],
  "details": "`BatchActivator.quote()` returned its input unchanged, the only activator with\nno escaping at all. `--prompt`, the `VIRTUALENV_PROMPT` environment variable,\nand the config file all set the prompt, and `activate.bat` writes it straight\ninto `@set \"VAR=value\"`. A prompt containing a double quote closes that string\nearly, and whatever follows runs as live cmd.exe syntax. For example, a venv\ncreated with `--prompt \u0027x\" \u0026 calc \u0026 \"\u0027` runs `calc` the moment someone runs\n`activate.bat`.\n\nAnyone who templates a prompt from untrusted input (a CI job using a branch\nname, a wrapper script deriving an environment name from user input) hands an\nattacker code execution in the shell of anyone who activates the resulting venv\non Windows.\n\nFixed in 21.7.12 by escaping the characters cmd.exe treats as live syntax\ninside this construct.\n",
  "id": "PYSEC-2026-4014",
  "modified": "2026-09-30T16:13:20.593341Z",
  "published": "2026-09-18T01:41:45Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/security/advisories/GHSA-x78j-v8h9-3j2q"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/pull/3250"
    },
    {
      "type": "FIX",
      "url": "https://github.com/pypa/virtualenv/commit/d721ff140ce4afdc2a9b76751e4584e25d9fbea6"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/releases/tag/21.7.12"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pypa/virtualenv"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/virtualenv"
    }
  ],
  "summary": "Command injection via --prompt in activate.bat (batch activator)"
}

BREW-CHARM-TOOLS-CVE-202… (PYSEC-2026-4014)

Vulnerability from osv_homebrew – Published: 2026-10-01 08:54 – Updated: 2026-10-01 08:54 – Source website

Summary

Command injection via --prompt in activate.bat (batch activator)

Details

Fixed in 21.7.12 by escaping the characters cmd.exe treats as live syntax inside this construct.

References

URL

Type

	https://github.com/pypa/virtualenv/security/advis…	WEB
	https://github.com/pypa/virtualenv/pull/3250	WEB
	https://github.com/pypa/virtualenv/commit/d721ff1…	FIX
	https://github.com/pypa/virtualenv/releases/tag/21.7.12	WEB
	https://github.com/pypa/virtualenv	PACKAGE
	https://pypi.org/project/virtualenv	PACKAGE

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": null,
        "range_state": "affected",
        "resource": "virtualenv",
        "resource_purl": "pkg:pypi/virtualenv@20.39.1",
        "upstream_fixed_in": "21.7.12"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "charm-tools",
        "purl": "pkg:brew/charm-tools"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.9.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/virtualenv@20.39.1",
        "name": "virtualenv",
        "resource": "virtualenv",
        "strategy": "registry",
        "subject_version": "20.39.1"
      }
    ]
  },
  "details": "`BatchActivator.quote()` returned its input unchanged, the only activator with\nno escaping at all. `--prompt`, the `VIRTUALENV_PROMPT` environment variable,\nand the config file all set the prompt, and `activate.bat` writes it straight\ninto `@set \"VAR=value\"`. A prompt containing a double quote closes that string\nearly, and whatever follows runs as live cmd.exe syntax. For example, a venv\ncreated with `--prompt \u0027x\" \u0026 calc \u0026 \"\u0027` runs `calc` the moment someone runs\n`activate.bat`.\n\nAnyone who templates a prompt from untrusted input (a CI job using a branch\nname, a wrapper script deriving an environment name from user input) hands an\nattacker code execution in the shell of anyone who activates the resulting venv\non Windows.\n\nFixed in 21.7.12 by escaping the characters cmd.exe treats as live syntax\ninside this construct.\n",
  "id": "BREW-charm-tools-CVE-2026-102937",
  "modified": "2026-10-01T08:54:28Z",
  "published": "2026-10-01T08:54:28Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/security/advisories/GHSA-x78j-v8h9-3j2q"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/pull/3250"
    },
    {
      "type": "FIX",
      "url": "https://github.com/pypa/virtualenv/commit/d721ff140ce4afdc2a9b76751e4584e25d9fbea6"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/releases/tag/21.7.12"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pypa/virtualenv"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/virtualenv"
    }
  ],
  "schema_version": "1.7.3",
  "summary": "Command injection via --prompt in activate.bat (batch activator)",
  "upstream": [
    "PYSEC-2026-4014",
    "CVE-2026-102937",
    "GHSA-x78j-v8h9-3j2q"
  ]
}

BREW-CLOUDISCOVERY-CVE-2… (PYSEC-2026-4014)

Vulnerability from osv_homebrew – Published: 2026-09-30 21:05 – Updated: 2026-09-30 21:05 – Source website

Summary

Command injection via --prompt in activate.bat (batch activator)

Details

Fixed in 21.7.12 by escaping the characters cmd.exe treats as live syntax inside this construct.

References

URL

Type

	https://github.com/pypa/virtualenv/security/advis…	WEB
	https://github.com/pypa/virtualenv/pull/3250	WEB
	https://github.com/pypa/virtualenv/commit/d721ff1…	FIX
	https://github.com/pypa/virtualenv/releases/tag/21.7.12	WEB
	https://github.com/pypa/virtualenv	PACKAGE
	https://pypi.org/project/virtualenv	PACKAGE

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": null,
        "range_state": "affected",
        "resource": "virtualenv",
        "resource_purl": "pkg:pypi/virtualenv@20.31.2",
        "upstream_fixed_in": "21.7.12"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "cloudiscovery",
        "purl": "pkg:brew/cloudiscovery"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.4.4_4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/virtualenv@20.31.2",
        "name": "virtualenv",
        "resource": "virtualenv",
        "strategy": "registry",
        "subject_version": "20.31.2"
      }
    ]
  },
  "details": "`BatchActivator.quote()` returned its input unchanged, the only activator with\nno escaping at all. `--prompt`, the `VIRTUALENV_PROMPT` environment variable,\nand the config file all set the prompt, and `activate.bat` writes it straight\ninto `@set \"VAR=value\"`. A prompt containing a double quote closes that string\nearly, and whatever follows runs as live cmd.exe syntax. For example, a venv\ncreated with `--prompt \u0027x\" \u0026 calc \u0026 \"\u0027` runs `calc` the moment someone runs\n`activate.bat`.\n\nAnyone who templates a prompt from untrusted input (a CI job using a branch\nname, a wrapper script deriving an environment name from user input) hands an\nattacker code execution in the shell of anyone who activates the resulting venv\non Windows.\n\nFixed in 21.7.12 by escaping the characters cmd.exe treats as live syntax\ninside this construct.\n",
  "id": "BREW-cloudiscovery-CVE-2026-102937",
  "modified": "2026-09-30T21:05:15Z",
  "published": "2026-09-30T21:05:15Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/security/advisories/GHSA-x78j-v8h9-3j2q"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/pull/3250"
    },
    {
      "type": "FIX",
      "url": "https://github.com/pypa/virtualenv/commit/d721ff140ce4afdc2a9b76751e4584e25d9fbea6"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/releases/tag/21.7.12"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pypa/virtualenv"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/virtualenv"
    }
  ],
  "schema_version": "1.7.3",
  "summary": "Command injection via --prompt in activate.bat (batch activator)",
  "upstream": [
    "PYSEC-2026-4014",
    "CVE-2026-102937",
    "GHSA-x78j-v8h9-3j2q"
  ]
}

CVE-2026-102937 (GCVE-0-2026-102937)

Vulnerability from cvelistv5 – Published: 2026-09-29 20:56 – Updated: 2026-09-29 20:56

Title

virtualenv: Command injection via --prompt in activate.bat (batch activator)

Summary

virtualenv is a tool for creating isolated virtual python environments. Prior to 21.7.12, BatchActivator.quote() returns prompt text unchanged before activate.bat inserts it into a cmd.exe set "VAR=value" statement. An attacker who influences --prompt, VIRTUALENV_PROMPT, or the corresponding configuration value can include a double quote that closes the assignment and leaves following cmd.exe operators as executable syntax. When a user activates the generated Windows environment, the injected commands run with that user's privileges. This issue is fixed in version 21.7.12.

Severity

7.3 (High)


                        
                          CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CWE

CWE-78 - Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Assigner

GitHub_M mitre root Scorecard

References

4 references

URL	Tags
https://github.com/pypa/virtualenv/security/advis…	x_refsource_CONFIRM
https://github.com/pypa/virtualenv/pull/3250	x_refsource_MISC
https://github.com/pypa/virtualenv/commit/d721ff1…	x_refsource_MISC
https://github.com/pypa/virtualenv/releases/tag/21.7.12	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
pypa	virtualenv	Affected: < 21.7.12

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "virtualenv",
          "vendor": "pypa",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 21.7.12"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "virtualenv is a tool for creating isolated virtual python environments. Prior to 21.7.12, BatchActivator.quote() returns prompt text unchanged before activate.bat inserts it into a cmd.exe set \"VAR=value\" statement. An attacker who influences --prompt, VIRTUALENV_PROMPT, or the corresponding configuration value can include a double quote that closes the assignment and leaves following cmd.exe operators as executable syntax. When a user activates the generated Windows environment, the injected commands run with that user\u0027s privileges. This issue is fixed in version 21.7.12."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "LOCAL",
            "baseScore": 7.3,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "PASSIVE",
            "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-78",
              "description": "CWE-78: Improper Neutralization of Special Elements used in an OS Command (\u0027OS Command Injection\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-29T20:56:13.998Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/pypa/virtualenv/security/advisories/GHSA-x78j-v8h9-3j2q",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/pypa/virtualenv/security/advisories/GHSA-x78j-v8h9-3j2q"
        },
        {
          "name": "https://github.com/pypa/virtualenv/pull/3250",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/pypa/virtualenv/pull/3250"
        },
        {
          "name": "https://github.com/pypa/virtualenv/commit/d721ff140ce4afdc2a9b76751e4584e25d9fbea6",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/pypa/virtualenv/commit/d721ff140ce4afdc2a9b76751e4584e25d9fbea6"
        },
        {
          "name": "https://github.com/pypa/virtualenv/releases/tag/21.7.12",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/pypa/virtualenv/releases/tag/21.7.12"
        }
      ],
      "source": {
        "advisory": "GHSA-x78j-v8h9-3j2q",
        "discovery": "UNKNOWN"
      },
      "title": "virtualenv: Command injection via --prompt in activate.bat (batch activator)"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-102937",
    "datePublished": "2026-09-29T20:56:13.998Z",
    "dateReserved": "2026-09-29T20:24:43.340Z",
    "dateUpdated": "2026-09-29T20:56:13.998Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

GHSA-X78J-V8H9-3J2Q

Vulnerability from github – Published: 2026-10-01 15:08 – Updated: 2026-10-01 15:08

Summary

virtualenv: Command injection via --prompt in activate.bat (batch activator)

Details

$ virtualenv --prompt 'x" & calc & "' venv
$ venv\Scripts\activate.bat

runs calc the moment someone activates the environment. Confirmed on a real Windows runner. Anyone who templates a prompt from untrusted input (a CI job using a branch name, a wrapper script deriving an environment name from user input) hands an attacker code execution in the shell of anyone who activates the resulting venv on Windows.

Fixed in 21.7.12 by escaping the characters cmd.exe treats as live syntax inside this construct. Fix: https://github.com/pypa/virtualenv/pull/3250

Severity

7.3 (High)


                  
                    CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Show details on source website

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 21.7.11"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "virtualenv"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "21.7.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-102937"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-78"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-01T15:08:29Z",
    "nvd_published_at": "2026-09-29T21:17:18Z",
    "severity": "HIGH"
  },
  "details": "`BatchActivator.quote()` returned its input unchanged, the only activator with no escaping at all. `--prompt`, the `VIRTUALENV_PROMPT` environment variable, and the config file all set the prompt, and `activate.bat` writes it straight into `@set \"VAR=value\"`. A prompt containing a double quote closes that string early, and whatever follows runs as live cmd.exe syntax:\n\n```console\n$ virtualenv --prompt \u0027x\" \u0026 calc \u0026 \"\u0027 venv\n$ venv\\Scripts\\activate.bat\n```\n\nruns `calc` the moment someone activates the environment. Confirmed on a real Windows runner. Anyone who templates a prompt from untrusted input (a CI job using a branch name, a wrapper script deriving an environment name from user input) hands an attacker code execution in the shell of anyone who activates the resulting venv on Windows.\n\nFixed in 21.7.12 by escaping the characters cmd.exe treats as live syntax inside this construct. Fix: https://github.com/pypa/virtualenv/pull/3250",
  "id": "GHSA-x78j-v8h9-3j2q",
  "modified": "2026-10-01T15:08:30Z",
  "published": "2026-10-01T15:08:29Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/security/advisories/GHSA-x78j-v8h9-3j2q"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-102937"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/pull/3250"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/commit/d721ff140ce4afdc2a9b76751e4584e25d9fbea6"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/virtualenv/PYSEC-2026-4014.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pypa/virtualenv"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/releases/tag/21.7.12"
    },
    {
      "type": "WEB",
      "url": "https://pypi.org/project/virtualenv"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "virtualenv: Command injection via --prompt in activate.bat (batch activator)"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Confirmed: The vulnerability has been validated from an analyst's perspective.
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Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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Action not permitted

PYSEC-2026-4014

BREW-CHARM-TOOLS-CVE-202… (PYSEC-2026-4014)

BREW-CLOUDISCOVERY-CVE-2… (PYSEC-2026-4014)

CVE-2026-102937 (GCVE-0-2026-102937)

GHSA-X78J-V8H9-3J2Q

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