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FKIE_CVE-2026-55244

Vulnerability from fkie_nvd - Published: 2026-09-14 20:16 - Updated: 2026-09-14 20:16
Severity
5.0 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
Summary
ASTEVAL is an evaluator of Python expressions and statements. Prior to 1.0.9, FROM_PY in asteval/astutils.py exposes BaseException, SystemExit, KeyboardInterrupt, and GeneratorExit to expressions evaluated by asteval.Interpreter.eval(), while run() and eval() in asteval/asteval.py catch Exception rather than these non-Exception BaseException subclasses. When an attacker-controlled expression raises one of these classes, on_raise() passes the class to raise_exception(), and the resulting exception bypasses the interpreter's safety handlers and propagates into the calling application. A consuming service that evaluates untrusted expressions can therefore be terminated or have signal and cleanup handling disrupted, causing denial of service. The separately documented read-only open() capability is not part of this vulnerability. This issue is fixed in version 1.0.9.
References
security-advisories@github.comhttps://github.com/lmfit/asteval/commit/9c625b3674f8d05f206708bb85afca17a87694a4
security-advisories@github.comhttps://github.com/lmfit/asteval/commit/c49c99a67acb63eb7410231932250bd820380e45
security-advisories@github.comhttps://github.com/lmfit/asteval/pull/153
security-advisories@github.comhttps://github.com/lmfit/asteval/releases/tag/1.0.9
security-advisories@github.comhttps://github.com/lmfit/asteval/security/advisories/GHSA-89v8-rhwq-hf77
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "asteval",
          "vendor": "lmfit",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.0.9"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "ASTEVAL is an evaluator of Python expressions and statements. Prior to 1.0.9, FROM_PY in asteval/astutils.py exposes BaseException, SystemExit, KeyboardInterrupt, and GeneratorExit to expressions evaluated by asteval.Interpreter.eval(), while run() and eval() in asteval/asteval.py catch Exception rather than these non-Exception BaseException subclasses. When an attacker-controlled expression raises one of these classes, on_raise() passes the class to raise_exception(), and the resulting exception bypasses the interpreter\u0027s safety handlers and propagates into the calling application. A consuming service that evaluates untrusted expressions can therefore be terminated or have signal and cleanup handling disrupted, causing denial of service. The separately documented read-only open() capability is not part of this vulnerability. This issue is fixed in version 1.0.9."
    }
  ],
  "id": "CVE-2026-55244",
  "lastModified": "2026-09-14T20:16:47.640",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.0,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.3,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-14T20:16:47.640",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/lmfit/asteval/commit/9c625b3674f8d05f206708bb85afca17a87694a4"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/lmfit/asteval/commit/c49c99a67acb63eb7410231932250bd820380e45"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/lmfit/asteval/pull/153"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/lmfit/asteval/releases/tag/1.0.9"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/lmfit/asteval/security/advisories/GHSA-89v8-rhwq-hf77"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-248"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.