{"id":"UBUNTU-CVE-2025-62494","details":"A type confusion vulnerability exists in the handling of the string addition (+) operation within the QuickJS engine.   *  The code first checks if the left-hand operand is a string.   *  It then attempts to convert the right-hand operand to a primitive value using JS_ToPrimitiveFree. This conversion can trigger a callback (e.g., toString or valueOf).   *  During this callback, an attacker can modify the type of the left-hand operand in memory, changing it from a string to a different type (e.g., an object or an array).   *  The code then proceeds to call JS_ConcatStringInPlace, which still treats the modified left-hand value as a string. This mismatch between the assumed type (string) and the actual type allows an attacker to control the data structure being processed by the concatenation logic, resulting in a type confusion condition. This can lead to out-of-bounds memory access, potentially resulting in memory corruption and arbitrary code execution in the context of the QuickJS runtime.","modified":"2026-05-20T16:23:39.262496231Z","published":"2025-10-16T16:15:00Z","upstream":["CVE-2025-62494"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2025-62494"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2025-62494"},{"type":"REPORT","url":"https://issuetracker.google.com/434193023"},{"type":"REPORT","url":"https://bellard.org/quickjs/Changelog"}],"affected":[{"package":{"name":"quickjs","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/quickjs?arch=source&distro=esm-apps%2Fnoble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2021.03.27-1","2021.03.27-1ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"libquickjs","binary_version":"2021.03.27-1ubuntu0.1~esm1"},{"binary_version":"2021.03.27-1ubuntu0.1~esm1","binary_name":"quickjs"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-62494.json"}},{"package":{"name":"quickjs","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/quickjs?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2024.01.13-5","2025.04.26-1"],"ecosystem_specific":{"binaries":[{"binary_name":"libquickjs","binary_version":"2025.04.26-1"},{"binary_name":"quickjs","binary_version":"2025.04.26-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-62494.json"}},{"package":{"name":"quickjs","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/quickjs?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2025.04.26-1","2025.04.26-1build1"],"ecosystem_specific":{"binaries":[{"binary_name":"libquickjs","binary_version":"2025.04.26-1build1"},{"binary_name":"quickjs","binary_version":"2025.04.26-1build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-62494.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:A/AC:H/AT:P/PR:L/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},{"type":"Ubuntu","score":"medium"}]}