{"id":"CVE-2020-24837","aliases":["EUVD-2020-17546","GHSA-qwpm-85r5-4m77"],"status":"published","title":"An integer underflow has been found in the latest version of ZCFees. The variables 'currPeriodIdx...","description":"An integer underflow has been found in the latest version of ZCFees. The variables 'currPeriodIdx' and 'lastPeriodExecIdx' are both unsigned integers, and the result of the minus operation may be a negative integer which leads to an underflow. The attackers can modify the current timestamp of the transaction somehow and block the execution of the process function.","severity":{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-12","score":0.01636,"percentile":0.76671,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-191"],"published":"2021-02-10T15:40:21Z","modified":"2026-06-17T03:06:05Z","products":[{"vendor":"zcfees_project","product":"zcfees"}],"references":[{"url":"https://etherscan.io/address/0x9d79c6e2a0222b9ac7bfabc447209c58fe9e0dcc#code","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2020-24837"},{"url":"https://github.com/advisories/GHSA-qwpm-85r5-4m77"}],"sources":{"cve":[{"id":"CVE-2020-24837","description":"An integer underflow has been found in the latest version of ZCFees. The variables 'currPeriodIdx' and 'lastPeriodExecIdx' are both unsigned integers, and the result of the minus operation may be a negative integer which leads to an underflow. The attackers can modify the current timestamp of the transaction somehow and block the execution of the process function.","status":"published","published":"2021-02-10T15:40:21Z","modified":"2024-08-04T15:19:09.437Z","updated_at":"2026-11-02T14:35:54.468882Z"}],"euvd":[{"id":"EUVD-2020-17546","description":"An integer underflow has been found in the latest version of ZCFees. The variables 'currPeriodIdx' and 'lastPeriodExecIdx' are both unsigned integers, and the result of the minus operation may be a negative integer which leads to an underflow. The attackers can modify the current timestamp of the transaction somehow and block the execution of the process function.","status":"published","published":"2021-02-10T15:40:21Z","modified":"2024-08-04T15:19:09Z","updated_at":"2026-11-03T03:07:19.210308Z"}],"ghsa":[{"id":"GHSA-qwpm-85r5-4m77","title":"An integer underflow has been found in the latest version of ZCFees. The variables 'currPeriodIdx...","description":"An integer underflow has been found in the latest version of ZCFees. The variables 'currPeriodIdx' and 'lastPeriodExecIdx' are both unsigned integers, and the result of the minus operation may be a negative integer which leads to an underflow. The attackers can modify the current timestamp of the transaction somehow and block the execution of the process function.","status":"published","published":"2022-05-24T17:41:41Z","modified":"2023-01-29T05:05:19Z","cwes":["CWE-191"],"updated_at":"2026-11-02T14:45:45.932105Z"}],"nvd":[{"id":"CVE-2020-24837","description":"An integer underflow has been found in the latest version of ZCFees. The variables 'currPeriodIdx' and 'lastPeriodExecIdx' are both unsigned integers, and the result of the minus operation may be a negative integer which leads to an underflow. The attackers can modify the current timestamp of the transaction somehow and block the execution of the process function.","status":"published","published":"2021-02-10T16:15:13.63Z","modified":"2026-06-17T03:06:05.62Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high","assessor":"primary"},{"version":"2.0","score":5,"vector":"AV:N/AC:L/Au:N/C:N/I:P/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-191"],"updated_at":"2026-11-02T14:06:34.188486Z"}]}}