{"schemaVersion":3,"id":"CVE-2021-28652","aliases":["ALPINE-CVE-2021-28652","UBUNTU-CVE-2021-28652","DEBIAN-CVE-2021-28652"],"status":"published","duplicateOf":null,"title":null,"description":"An issue was discovered in Squid before 4.15 and 5.x before 5.0.6. Due to incorrect parser validation, it allows a Denial of Service attack against the Cache Manager API. This allows a trusted client to trigger memory leaks that. over time, lead to a Denial of Service via an unspecified short query string. This attack is limited to clients with Cache Manager API access privilege.","dates":{"published":"2021-05-27T00:00:00.000Z","modified":"2024-08-03T21:47:33.045Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":4.9,"severity":"medium","version":"3.1","versionLabel":"v3.1","source":"NVD","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"OSV · Alpine","score":4.9,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","exploitability":3.1,"impact":6,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Ubuntu","score":4.9,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","exploitability":3.1,"impact":6,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Debian","score":4.9,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","exploitability":3.1,"impact":6,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":4.9,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","exploitability":null,"impact":null,"computed":false},{"version":"2.0","versionLabel":"v2.0","source":"NVD","score":4,"severity":"medium","vector":"AV:N/AC:L/Au:S/C:N/I:N/A:P","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.04341,"percentile":0.91086,"severity":"low","asOf":"2026-10-18T00:00:00.000Z","change":{"pp":0,"baselineDate":"2026-09-18T00:00:00.000Z","baselineScore":0.04341},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.04341,"percentile":0.91086}],"last30":[{"date":"2026-09-18T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.04341,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.04341,"percentile":0.91086}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[{"id":"REF_3B9856A328C39927","name":"Exploit Reference (bugs.squid-cache.org)","source":"reference","url":"https://bugs.squid-cache.org/show_bug.cgi?id=5106","maturity":"unknown","reliabilityScore":0.2,"verified":false,"type":null,"platforms":[],"requiresAuth":null,"exploitdb":null,"metasploit":null}],"exploitCount":1,"weaknesses":[{"id":"CWE-401","name":"Missing Release of Memory after Effective Lifetime","description":"The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.","type":"weakness","status":"Draft","abstraction":"Variant","likelihoodOfExploit":"Medium","url":"https://cwe.mitre.org/data/definitions/401.html"}],"affected":[{"vendor":"alpine","product":"squid","name":"squid","label":"squid","ecosystem":"Alpine Linux","cpePart":null,"purl":"pkg:apk/alpine/squid","purlType":"apk","versions":[{"text":"≥ 1.0, < 4.15-r0","noFixRecorded":false,"fixedIn":null},{"text":"≥ 1.0, < 5.0.6-r0","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 1.0, < 4.15-r0 | ≥ 1.0, < 5.0.6-r0","eol":null,"hubHref":null},{"vendor":"debian","product":"squid","name":"squid","label":"squid","ecosystem":"Debian","cpePart":null,"purl":"pkg:deb/debian/squid","purlType":"deb","versions":[{"text":"< 4.13-10","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 4.13-10","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"squid","name":"squid","label":"squid","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/squid","purlType":"deb","versions":[{"text":"< 4.10-1ubuntu1.4","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 4.10-1ubuntu1.4","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"squid3","name":"squid3","label":"squid3","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/squid3","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null},{"text":"< 3.5.27-1ubuntu1.11","noFixRecorded":false,"fixedIn":null}],"versionsText":"All versions (No fix recorded) | < 3.5.27-1ubuntu1.11","eol":null,"hubHref":null},{"vendor":"debian","product":"debian_linux","name":"debian linux","label":"debian_linux","ecosystem":null,"cpePart":"o","purl":null,"purlType":null,"versions":[{"text":"9.0","noFixRecorded":false,"fixedIn":null},{"text":"10.0","noFixRecorded":false,"fixedIn":null}],"versionsText":"9.0 | 10.0","eol":{"isEol":true,"eolDate":"2022-07-01T00:00:00.000Z","matchMethod":"cpe","cycle":{"name":"9","label":"9 (Stretch)","eolFrom":"2022-07-01T00:00:00.000Z","isLts":false,"isMaintained":true,"latestVersion":"9.13"},"product":{"name":"debian","label":"Debian","category":"os"}},"hubHref":"/vendor/debian/debian_linux"},{"vendor":"fedoraproject","product":"fedora","name":"fedora","label":"fedora","ecosystem":null,"cpePart":"o","purl":null,"purlType":null,"versions":[{"text":"33","noFixRecorded":false,"fixedIn":null},{"text":"34","noFixRecorded":false,"fixedIn":null}],"versionsText":"33 | 34","eol":{"isEol":true,"eolDate":"2021-11-30T00:00:00.000Z","matchMethod":"cpe","cycle":{"name":"33","label":"33","eolFrom":"2021-11-30T00:00:00.000Z","isLts":false,"isMaintained":false,"latestVersion":null},"product":{"name":"fedora","label":"Fedora Linux","category":"os"}},"hubHref":"/vendor/fedoraproject/fedora"},{"vendor":"squid-cache","product":"squid","name":"squid","label":"squid","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 1.0, < 4.15","noFixRecorded":false,"fixedIn":null},{"text":"≥ 5.0, < 5.0.6","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 1.0, < 4.15 | ≥ 5.0, < 5.0.6","eol":{"isEol":null,"eolDate":null,"matchMethod":"cpe","cycle":null,"product":{"name":"squid","label":"Squid","category":"server-app"}},"hubHref":"/vendor/squid-cache/squid"}],"affectedCount":7,"eol":{"hasEol":true,"count":2},"references":[{"url":"https://bugs.squid-cache.org/show_bug.cgi?id=5106","label":"bugs.squid-cache.org/show_bug.cgi?id=5106","hostname":"bugs.squid-cache.org","tags":["Exploit","Issue Tracking","Vendor Advisory"]},{"url":"https://github.com/squid-cache/squid/security/advisories/GHSA-m47m-9hvw-7447","label":"github.com/squid-cache/squid/security/advisories/GHSA-m47m-9hvw-7447","hostname":"github.com","tags":["REPORT","Patch","Third Party Advisory"]},{"url":"https://www.debian.org/security/2021/dsa-4924","label":"www.debian.org/security/2021/dsa-4924","hostname":"www.debian.org","tags":["Vendor Advisory","Third Party Advisory"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LSQ3U54ZCNXR44QRPW3AV2VCS6K3TKCF/","label":"lists.fedoraproject.org/archives/…","hostname":"lists.fedoraproject.org","tags":["Vendor Advisory"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T4EPIWUZDJAXADDHVOPKRBTQHPBR6H66/","label":"lists.fedoraproject.org/archives/…","hostname":"lists.fedoraproject.org","tags":["Vendor Advisory"]},{"url":"https://lists.debian.org/debian-lts-announce/2021/06/msg00014.html","label":"lists.debian.org/debian-lts-announce/2021/06/msg00014.html","hostname":"lists.debian.org","tags":["Mailing List","Third Party Advisory"]},{"url":"http://www.openwall.com/lists/oss-security/2023/10/11/3","label":"www.openwall.com/lists/oss-security/2023/10/11/3","hostname":"www.openwall.com","tags":["Mailing List","Third Party Advisory"]},{"url":"http://seclists.org/fulldisclosure/2023/Oct/14","label":"seclists.org/fulldisclosure/2023/Oct/14","hostname":"seclists.org","tags":["Mailing List","Third Party Advisory"]},{"url":"https://security.alpinelinux.org/vuln/CVE-2021-28652","label":"security.alpinelinux.org/vuln/CVE-2021-28652","hostname":"security.alpinelinux.org","tags":["Advisory"]},{"url":"https://ubuntu.com/security/CVE-2021-28652","label":"ubuntu.com/security/CVE-2021-28652","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/notices/USN-4981-1","label":"ubuntu.com/security/notices/USN-4981-1","hostname":"ubuntu.com","tags":["Advisory"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-28652","label":"www.cve.org/CVERecord?id=CVE-2021-28652","hostname":"www.cve.org","tags":["REPORT"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2021-28652","label":"security-tracker.debian.org/tracker/CVE-2021-28652","hostname":"security-tracker.debian.org","tags":["Advisory"]}],"lineage":{"upstream":[],"downstream":["DLA-2685-1","DSA-4924-1","MGASA-2021-0237","OPENSUSE-SU-2021:0879-1","OPENSUSE-SU-2021:1961-1","OPENSUSE-SU-2024:11403-1","RHSA-2021:4292","SUSE-SU-2021:1838-1","SUSE-SU-2021:1961-1","USN-4981-1"],"duplicates":[],"related":["OPENSUSE-SU-2021:0879-1","OPENSUSE-SU-2021:1961-1","OPENSUSE-SU-2024:11403-1","SUSE-SU-2021:1838-1","SUSE-SU-2021:1961-1","USN-4981-1"]},"timeline":[{"kind":"published","date":"2021-05-27T00:00:00.000Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2024-08-03T21:47:33.045Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":30,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-19T12:50:44.711Z","stale":false,"partial":false}}