{
    "data_version": "4.0",
    "data_type": "CVE",
    "data_format": "MITRE",
    "CVE_data_meta": {
        "ID": "CVE-2023-4039",
        "ASSIGNER": "arm-security@arm.com",
        "STATE": "PUBLIC"
    },
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "** DISPUTED ** \n\n**DISPUTED**A failure in the -fstack-protector feature in GCC-based toolchains \nthat target AArch64 allows an attacker to exploit an existing buffer \noverflow in dynamically-sized local variables in your application \nwithout this being detected. This stack-protector failure only applies \nto C99-style dynamically-sized local variables or those created using \nalloca(). The stack-protector operates as intended for statically-sized \nlocal variables.\n\nThe default behavior when the stack-protector \ndetects an overflow is to terminate your application, resulting in \ncontrolled loss of availability. An attacker who can exploit a buffer \noverflow without triggering the stack-protector might be able to change \nprogram flow control to cause an uncontrolled loss of availability or to\n go further and affect confidentiality or integrity. NOTE: The GCC project argues that this is a missed hardening bug and not a vulnerability by itself.\n\n\n\n\n\n"
            }
        ]
    },
    "problemtype": {
        "problemtype_data": [
            {
                "description": [
                    {
                        "lang": "eng",
                        "value": "CWE-693 Protection Mechanism Failure",
                        "cweId": "CWE-693"
                    }
                ]
            }
        ]
    },
    "affects": {
        "vendor": {
            "vendor_data": [
                {
                    "vendor_name": "Arm Ltd",
                    "product": {
                        "product_data": [
                            {
                                "product_name": "Arm GNU Toolchain",
                                "version": {
                                    "version_data": [
                                        {
                                            "version_value": "not down converted",
                                            "x_cve_json_5_version_data": {
                                                "versions": [
                                                    {
                                                        "status": "affected",
                                                        "version": "All versions where option -fstack-protector is used"
                                                    }
                                                ],
                                                "defaultStatus": "affected"
                                            }
                                        }
                                    ]
                                }
                            }
                        ]
                    }
                },
                {
                    "vendor_name": "GNU",
                    "product": {
                        "product_data": [
                            {
                                "product_name": "GCC",
                                "version": {
                                    "version_data": [
                                        {
                                            "version_affected": "=",
                                            "version_value": "All versions of GCC that target AArch64 when option -fstack-protector is used"
                                        }
                                    ]
                                }
                            }
                        ]
                    }
                }
            ]
        }
    },
    "references": {
        "reference_data": [
            {
                "url": "https://developer.arm.com/Arm%20Security%20Center/GCC%20Stack%20Protector%20Vulnerability%20AArch64",
                "refsource": "MISC",
                "name": "https://developer.arm.com/Arm%20Security%20Center/GCC%20Stack%20Protector%20Vulnerability%20AArch64"
            },
            {
                "url": "https://github.com/metaredteam/external-disclosures/security/advisories/GHSA-x7ch-h5rf-w2mf",
                "refsource": "MISC",
                "name": "https://github.com/metaredteam/external-disclosures/security/advisories/GHSA-x7ch-h5rf-w2mf"
            }
        ]
    },
    "generator": {
        "engine": "Vulnogram 0.1.0-dev"
    },
    "source": {
        "discovery": "EXTERNAL"
    },
    "configuration": [
        {
            "lang": "en",
            "supportingMedia": [
                {
                    "base64": false,
                    "type": "text/html",
                    "value": "\nThe specific conditions where the stack-protector fails to give the desired level of protection are when:\n\n\n<ul>\n    <li>using GCC (all unpatched versions) targeting AArch64</li>\n    <li>and when the -fstack-protector option is used</li>\n    <li>and when the program uses C99-style dynamically-sized local variables or alloca()</li>\n</ul>\n<p>And to be exploitable there must also be a prior vulnerability in the\n program such that an attacker can cause a buffer overflow in these \nlocal variables that overwrites saved register values in the stack.</p>\n\n<br>"
                }
            ],
            "value": "The specific conditions where the stack-protector fails to give the desired level of protection are when:\n\n\n\n      *  using GCC (all unpatched versions) targeting AArch64\n\n      *  and when the -fstack-protector option is used\n\n      *  and when the program uses C99-style dynamically-sized local variables or alloca()\n\n\n\n\nAnd to be exploitable there must also be a prior vulnerability in the\n program such that an attacker can cause a buffer overflow in these \nlocal variables that overwrites saved register values in the stack.\n\n\n\n\n"
        }
    ],
    "solution": [
        {
            "lang": "en",
            "supportingMedia": [
                {
                    "base64": false,
                    "type": "text/html",
                    "value": "\nRecompile vulnerable code using an updated toolchain.\n\n<br>"
                }
            ],
            "value": "Recompile vulnerable code using an updated toolchain.\n\n\n"
        }
    ],
    "credits": [
        {
            "lang": "en",
            "value": "Tom Hebb from Meta Red Team X and Maria Markstedter from Azeria Labs"
        }
    ],
    "impact": {
        "cvss": [
            {
                "attackComplexity": "HIGH",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 4.8,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "LOW",
                "integrityImpact": "LOW",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N",
                "version": "3.1"
            }
        ]
    }
}