ASTEVAL Vulnerable to Maliciously Crafted Format Strings Leading to Sandbox Escape

{
  "id": "841bf0ddb5d43a25cd9808c7a5db5b373ff76620f95152023e296dbe904f6aef",
  "url": "https://osv.dev/vulnerability/CVE-2025-24359",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ASTEVAL Vulnerable to Maliciously Crafted Format Strings Leading to Sandbox Escape",
    "summary": "ASTEVAL is an evaluator of Python expressions and statements. Prior to version 1.0.6, if an attacker can control the input to the `asteval` library, they can bypass asteval's restrictions and execute arbitrary Python code in the context of the application using the library. The vulnerability is rooted in how `asteval` performs handling of `FormattedValue` AST nodes. In particular, the `on_formattedvalue` value uses the dangerous format method of the str class. The code allows an attacker to manipulate the value of the string used in the dangerous call `fmt.format(__fstring__=val)`. This vulnerability can be exploited to access protected attributes by intentionally triggering an `AttributeError` exception. The attacker can then catch the exception and use its `obj` attribute to gain arbitrary access to sensitive or protected object properties. Version 1.0.6 fixes this issue.",
    "evidence": "osv:CVE-2025-24359",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2025-24359",
      "aliases": [
        "CVE-2025-24359",
        "GHSA-3wwr-3g9f-9gc7",
        "PYSEC-2026-1195"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/lmfit/asteval",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "40c31962bbdfe1012aacca1892a8d9263a67258e"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.0.6"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.0.6"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "versions": [
            "1.0.5",
            "1.0.4",
            "1.0.3",
            "1.0.2",
            "1.0.1",
            "1.0.0",
            "0.9.33",
            "0.9.32",
            "0.9.31",
            "0.9.30",
            "0.9.29",
            "0.9.28",
            "0.9.27",
            "0.9.26",
            "0.9.25",
            "0.9.24",
            "0.9.23",
            "0.9.22",
            "0.9.21",
            "0.9.20",
            "0.9.19",
            "0.9.18",
            "0.9.17",
            "0.9.16",
            "0.9.15",
            "0.9.14",
            "0.9.13",
            "0.9.12",
            "0.9.11",
            "0.9.10",
            "0.9.9",
            "0.9.7",
            "0.9.6",
            "0.9.5",
            "0.9.4",
            "0.9.3.1",
            "0.9.3",
            "0.9.2",
            "0.9.1",
            "0.9"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-24359.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:23.955637219Z",
      "provider": "osv",
      "references": [
        "https://github.com/lmfit/asteval/blob/cfb57f0beebe0dc0520a1fbabc35e66060c7ea71/asteval/asteval.py#L507",
        "https://lucumr.pocoo.org/2016/12/29/careful-with-str-format",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/24xxx/CVE-2025-24359.json",
        "https://github.com/lmfit/asteval/security/advisories/GHSA-3wwr-3g9f-9gc7",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-24359"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-134",
          "CWE-749"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/24xxx/CVE-2025-24359.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-24359",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 490473,
  "published_at": "2025-01-24T16:52:44.304+00:00"
}