{"id":"CVE-2023-4039","title":"**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 d…","summary":"**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 d…","severity":"medium","cvss":4.8,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N","cwe":["CWE-693"],"vendor":"gnu","product":"gcc","affected":["gcc < 2023-09-12"],"patched":["gcc 2023-09-12"],"published":"2023-09-13","updated":"2026-10-14","sourceUpdated":"2026-10-14T22:17:17.000","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2023-4039","references":[{"url":"https://developer.arm.com/Arm%20Security%20Center/GCC%20Stack%20Protector%20Vulnerability%20AArch64","label":"arm-security@arm.com"},{"url":"https://github.com/metaredteam/external-disclosures/security/advisories/GHSA-x7ch-h5rf-w2mf","label":"arm-security@arm.com"},{"url":"https://developer.arm.com/Arm%20Security%20Center/GCC%20Stack%20Protector%20Vulnerability%20AArch64","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/metaredteam/external-disclosures/security/advisories/GHSA-x7ch-h5rf-w2mf","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-355557.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-398330.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org","exploit-available"],"epss":0.01036,"epssPercentile":0.63726,"ingestedAt":"2026-06-29T13:24:33.901Z","exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2025-06-03T16:04:55.934999Z"},"slug":"CVE-2023-4039","body":"## Overview\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## Affected\n\n- `gcc < 2023-09-12`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `gcc 2023-09-12`","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":26.4,"likelihood":0.2,"exploitation":12,"ransomware":0},"changes":[{"seq":221948,"id":"CVE-2023-4039","ts":1792039668433,"field":"exploit_available","old":"false","new":"true"}]}