{"id":"CVE-2021-21707","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-21707","generatedAt":"2026-11-05T00:59:06.791Z","title":"In PHP versions 7.3.x below 7.3.33, 7.4.x below 7.4.26 and 8.0.x below 8.0.13, certain XML parsing functions, like simplexml_load_file(), URL-decode the filename passed to them.","description":"In PHP versions 7.3.x below 7.3.33, 7.4.x below 7.4.26 and 8.0.x below 8.0.13, certain XML parsing functions, like simplexml_load_file(), URL-decode the filename passed to them. If that filename contains URL-encoded NUL character, this may cause the function to interpret this as the end of the filename, thus interpreting the filename differently from what the user intended, which may lead it to reading a different file than intended.","published":"2021-11-29T07:15:06.000Z","lastModified":"2026-06-17T03:36:02.000Z","status":"Modified","sourceIdentifier":"security@php.net","cvss":{"version":"3.1","score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"},"cwe":["CWE-159"],"affected":["php/php","netapp/clustered data ontap","debian/debian linux","tenable/tenable.sc"],"epss":{"score":0.25315,"percentile":0.97945,"date":"2026-11-03","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"EPSS puts the probability of exploitation in the next 30 days at 25.3%, higher than 98% of all known CVEs. Patch or mitigate before the next change window."},"changes":[],"references":[{"url":"https://bugs.php.net/bug.php?id=79971","tags":["Exploit","Issue Tracking","Patch","Release Notes","Vendor Advisory"],"source":"security@php.net"},{"url":"https://lists.debian.org/debian-lts-announce/2022/12/msg00030.html","tags":["Issue Tracking","Mailing List"],"source":"security@php.net"},{"url":"https://security.netapp.com/advisory/ntap-20211223-0005/","tags":["Third Party Advisory"],"source":"security@php.net"},{"url":"https://www.debian.org/security/2022/dsa-5082","tags":["Third Party Advisory"],"source":"security@php.net"},{"url":"https://www.tenable.com/security/tns-2022-09","tags":["Patch","Release Notes","Third Party Advisory"],"source":"security@php.net"},{"url":"https://bugs.php.net/bug.php?id=79971","tags":["Exploit","Issue Tracking","Patch","Release Notes","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2022/12/msg00030.html","tags":["Issue Tracking","Mailing List"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20211223-0005/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2022/dsa-5082","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.tenable.com/security/tns-2022-09","tags":["Patch","Release Notes","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-21707","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."}