CVE-2026-113721 (GCVE-0-2026-113721)

Vulnerability from cvelistv5 – Published: 2026-10-20 19:46 – Updated: 2026-10-20 19:46
VLAI
Title
virtualenv: Generated files can follow existing destination links
Summary
virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, ViaTemplateActivator._generate() removes an existing output only when Path.exists() is true, allowing a dangling symlink to survive and redirect generated activation content, while PyEnvCfg.write() opens pyvenv.cfg without first replacing an existing symbolic or hard link. Another local account that prepares final entries inside the destination can therefore cause environment creation to create or overwrite files outside the requested tree with constrained virtualenv-generated content and the invoking user's permissions. The destination parent must remain controlled by the environment owner during creation; concurrent parent-directory replacement is a separate concern. This issue is fixed in version 21.14.9.
Severity
4.5 (Medium)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
CWE
  • CWE-59 - Improper Link Resolution Before File Access ('Link Following')
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7638 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
pypa virtualenv Affected: < 21.14.9
guessed Create a notification for this product.
Show details on NVD website
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "virtualenv",
          "vendor": "pypa",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 21.14.9"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, ViaTemplateActivator._generate() removes an existing output only when Path.exists() is true, allowing a dangling symlink to survive and redirect generated activation content, while PyEnvCfg.write() opens pyvenv.cfg without first replacing an existing symbolic or hard link. Another local account that prepares final entries inside the destination can therefore cause environment creation to create or overwrite files outside the requested tree with constrained virtualenv-generated content and the invoking user\u0027s permissions. The destination parent must remain controlled by the environment owner during creation; concurrent parent-directory replacement is a separate concern. This issue is fixed in version 21.14.9."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "LOCAL",
            "availabilityImpact": "LOW",
            "baseScore": 4.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-59",
              "description": "CWE-59: Improper Link Resolution Before File Access (\u0027Link Following\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-20T19:46:28.770Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/pypa/virtualenv/security/advisories/GHSA-558c-9hv2-4prj",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/pypa/virtualenv/security/advisories/GHSA-558c-9hv2-4prj"
        },
        {
          "name": "https://github.com/pypa/virtualenv/pull/3431",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/pypa/virtualenv/pull/3431"
        },
        {
          "name": "https://github.com/pypa/virtualenv/commit/d25f28699eefb1fc34a251e5adf2b5de844c36cd",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/pypa/virtualenv/commit/d25f28699eefb1fc34a251e5adf2b5de844c36cd"
        },
        {
          "name": "https://github.com/pypa/virtualenv/releases/tag/21.14.9",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/pypa/virtualenv/releases/tag/21.14.9"
        }
      ],
      "source": {
        "advisory": "GHSA-558c-9hv2-4prj",
        "discovery": "UNKNOWN"
      },
      "title": "virtualenv: Generated files can follow existing destination links"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-113721",
    "datePublished": "2026-10-20T19:46:28.770Z",
    "dateReserved": "2026-10-20T16:03:14.863Z",
    "dateUpdated": "2026-10-20T19:46:28.770Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-113721",
      "date": "2026-10-22",
      "epss": "0.00117",
      "percentile": "0.01569"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "virtualenv",
                "vendor": "pypa",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003c 21.14.9"
                  }
                ]
              }
            ],
            "source": "security-advisories@github.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, ViaTemplateActivator._generate() removes an existing output only when Path.exists() is true, allowing a dangling symlink to survive and redirect generated activation content, while PyEnvCfg.write() opens pyvenv.cfg without first replacing an existing symbolic or hard link. Another local account that prepares final entries inside the destination can therefore cause environment creation to create or overwrite files outside the requested tree with constrained virtualenv-generated content and the invoking user\u0027s permissions. The destination parent must remain controlled by the environment owner during creation; concurrent parent-directory replacement is a separate concern. This issue is fixed in version 21.14.9."
          }
        ],
        "id": "CVE-2026-113721",
        "lastModified": "2026-10-20T20:17:18.653",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "HIGH",
                "attackVector": "LOCAL",
                "availabilityImpact": "LOW",
                "baseScore": 4.5,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "LOW",
                "integrityImpact": "LOW",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L",
                "version": "3.1"
              },
              "exploitabilityScore": 1.0,
              "impactScore": 3.4,
              "source": "security-advisories@github.com",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-10-20T20:17:18.653",
        "references": [
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/pypa/virtualenv/commit/d25f28699eefb1fc34a251e5adf2b5de844c36cd"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/pypa/virtualenv/pull/3431"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/pypa/virtualenv/releases/tag/21.14.9"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/pypa/virtualenv/security/advisories/GHSA-558c-9hv2-4prj"
          }
        ],
        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Received",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-59"
              }
            ],
            "source": "security-advisories@github.com",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-10-20T20:22:21+00:00",
      "cve": "CVE-2026-113721",
      "id": "CVE-2026-113721",
      "initial_release_date": "2026-10-20T19:46:28.770000+00:00",
      "product_status:known_affected": "26",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "virtualenv: virtualenv: Arbitrary file overwrite via insecure symlink handling",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-113721.json",
      "version": "3"
    }
  }
}



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