Vulnerability from bitnami_vulndb
Published
2025-08-11 13:53
Modified
2025-08-11 14:19
Summary
Use-after-free in "unicode_escape" decoder with error handler
Details

There is an issue in CPython when using bytes.decode("unicode_escape", error="ignore|replace"). If you are not using the "unicode_escape" encoding or an error handler your usage is not affected. To work-around this issue you may stop using the error= handler and instead wrap the bytes.decode() call in a try-except catching the DecodeError.

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "libpython",
        "purl": "pkg:bitnami/libpython"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.9.23"
            },
            {
              "introduced": "3.10.0"
            },
            {
              "fixed": "3.10.18"
            },
            {
              "introduced": "3.11.0"
            },
            {
              "fixed": "3.11.13"
            },
            {
              "introduced": "3.12.0"
            },
            {
              "fixed": "3.12.11"
            },
            {
              "introduced": "3.13.0"
            },
            {
              "fixed": "3.13.4"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "type": "CVSS_V4"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-4516"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:python:python:*:*:*:*:*:*:*:*"
    ],
    "severity": "Medium"
  },
  "details": "There is an issue in CPython when using `bytes.decode(\"unicode_escape\", error=\"ignore|replace\")`. If you are not using the \"unicode_escape\" encoding or an error handler your usage is not affected. To work-around this issue you may stop using the error= handler and instead wrap the bytes.decode() call in a try-except catching the DecodeError.",
  "id": "BIT-libpython-2025-4516",
  "modified": "2025-08-11T14:19:40.295Z",
  "published": "2025-08-11T13:53:13.759Z",
  "references": [
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2025/05/16/4"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2025/05/19/1"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/4398b788ffc1f954a2c552da285477d42a571292"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/6279eb8c076d89d3739a6edb393e43c7929b429d"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/69b4387f78f413e8c47572a85b3478c47eba8142"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/73b3040f592436385007918887b7e2132aa8431f"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/8d35fd1b34935221aff23a1ab69a429dd156be77"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/9f69a58623bd01349a18ba0c7a9cb1dad6a51e8e"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/ab9893c40609935e0d40a6d2a7307ea51aec598b"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/issues/133767"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/pull/129648"
    },
    {
      "type": "WEB",
      "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/L75IPBBTSCYEF56I2M4KIW353BB3AY74/"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-4516"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "Use-after-free in \"unicode_escape\" decoder with error handler"
}


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