{"id":"CVE-2021-39275","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-39275","generatedAt":"2026-11-05T01:11:12.737Z","title":"ap_escape_quotes() may write beyond the end of a buffer when given malicious input.","description":"ap_escape_quotes() may write beyond the end of a buffer when given malicious input. No included modules pass untrusted data to these functions, but third-party / external modules may. This issue affects Apache HTTP Server 2.4.48 and earlier.","published":"2021-09-16T15:15:08.000Z","lastModified":"2026-06-17T04:03:27.000Z","status":"Analyzed","sourceIdentifier":"security@apache.org","cvss":{"version":"3.1","score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-787"],"affected":["apache/http server","fedoraproject/fedora","debian/debian linux","netapp/cloud backup","netapp/clustered data ontap","netapp/storagegrid","oracle/http server","oracle/instantis enterprisetrack","oracle/zfs storage appliance kit","siemens/sinec nms","siemens/sinema server"],"epss":{"score":0.39402,"percentile":0.9861,"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 39.4%, higher than 99% of all known CVEs. Patch or mitigate before the next change window."},"changes":[],"references":[{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-685781.pdf","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://httpd.apache.org/security/vulnerabilities_24.html","tags":["Release Notes","Vendor Advisory"],"source":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432%40%3Cusers.httpd.apache.org%3E","tags":["Patch"],"source":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r61fdbfc26ab170f4e6492ef3bd5197c20b862ce156e9d5a54d4b899c%40%3Cusers.httpd.apache.org%3E","tags":["Patch"],"source":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697%40%3Cusers.httpd.apache.org%3E","tags":["Patch"],"source":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r82c077663f9759c7df5a6656f925b3ee4f55fcd33c889ba7cd687029%40%3Cusers.httpd.apache.org%3E","tags":["Patch"],"source":"security@apache.org"},{"url":"https://lists.debian.org/debian-lts-announce/2021/10/msg00001.html","tags":["Mailing List","Third Party Advisory"],"source":"security@apache.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://security.gentoo.org/glsa/202208-20","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://security.netapp.com/advisory/ntap-20211008-0004/","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQ","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://www.debian.org/security/2021/dsa-4982","tags":["Third Party Advisory"],"source":"security@apache.org"},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","tags":["Patch","Third Party Advisory"],"source":"security@apache.org"},{"url":"https://www.oracle.com/security-alerts/cpujan2022.html","tags":["Patch","Third Party Advisory"],"source":"security@apache.org"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-685781.pdf","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://httpd.apache.org/security/vulnerabilities_24.html","tags":["Release Notes","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432%40%3Cusers.httpd.apache.org%3E","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r61fdbfc26ab170f4e6492ef3bd5197c20b862ce156e9d5a54d4b899c%40%3Cusers.httpd.apache.org%3E","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697%40%3Cusers.httpd.apache.org%3E","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r82c077663f9759c7df5a6656f925b3ee4f55fcd33c889ba7cd687029%40%3Cusers.httpd.apache.org%3E","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2021/10/msg00001.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/202208-20","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20211008-0004/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQ","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2021/dsa-4982","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpujan2022.html","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-39275","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."}