{"id":"CVE-2021-21704","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-21704","generatedAt":"2026-10-28T06:36:08.455Z","title":"In PHP versions 7.3.x below 7.3.29, 7.4.x below 7.4.21 and 8.0.x below 8.0.8, when using Firebird PDO driver extension, a malicious database server could cause crashes in various database functions, such as getAttribute(), execute(), fetch() and others…","description":"In PHP versions 7.3.x below 7.3.29, 7.4.x below 7.4.21 and 8.0.x below 8.0.8, when using Firebird PDO driver extension, a malicious database server could cause crashes in various database functions, such as getAttribute(), execute(), fetch() and others by returning invalid response data that is not parsed correctly by the driver. This can result in crashes, denial of service or potentially memory corruption.","published":"2021-10-04T04:15:08.000Z","lastModified":"2026-06-17T03:36:02.000Z","status":"Modified","sourceIdentifier":"security@php.net","cvss":{"version":"3.1","score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-125","CWE-190","CWE-787"],"affected":["php/php","netapp/clustered data ontap"],"epss":{"score":0.01796,"percentile":0.78321,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (1.80%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://bugs.php.net/bug.php?id=76448","tags":["Exploit","Issue Tracking","Patch","Vendor Advisory"],"source":"security@php.net"},{"url":"https://bugs.php.net/bug.php?id=76449","tags":["Exploit","Issue Tracking","Patch","Vendor Advisory"],"source":"security@php.net"},{"url":"https://bugs.php.net/bug.php?id=76450","tags":["Exploit","Issue Tracking","Patch","Vendor Advisory"],"source":"security@php.net"},{"url":"https://bugs.php.net/bug.php?id=76452","tags":["Exploit","Issue Tracking","Patch","Vendor Advisory"],"source":"security@php.net"},{"url":"https://security.gentoo.org/glsa/202209-20","tags":["Third Party Advisory"],"source":"security@php.net"},{"url":"https://security.netapp.com/advisory/ntap-20211029-0006/","tags":["Third Party Advisory"],"source":"security@php.net"},{"url":"https://bugs.php.net/bug.php?id=76448","tags":["Exploit","Issue Tracking","Patch","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://bugs.php.net/bug.php?id=76449","tags":["Exploit","Issue Tracking","Patch","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://bugs.php.net/bug.php?id=76450","tags":["Exploit","Issue Tracking","Patch","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://bugs.php.net/bug.php?id=76452","tags":["Exploit","Issue Tracking","Patch","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/202209-20","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20211029-0006/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-21704","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}