{"schemaVersion":3,"id":"USN-4994-2","aliases":[],"status":"published","duplicateOf":null,"title":null,"description":"apache2 vulnerabilities\n\nUSN-4994-1 fixed several vulnerabilities in Apache. This update provides\nthe corresponding update for Ubuntu 14.04 ESM and Ubuntu 16.04 ESM.\n\nOriginal advisory details:\n\n Antonio Morales discovered that the Apache mod_auth_digest module\n incorrectly handled certain Digest nonces. A remote attacker could possibly\n use this issue to cause Apache to crash, resulting in a denial of service.\n (CVE-2020-35452)\n\n Antonio Morales discovered that the Apache mod_session module incorrectly\n handled certain Cookie headers. A remote attacker could possibly use this\n issue to cause Apache to crash, resulting in a denial of service.\n (CVE-2021-26690)\n\n Christophe Jaillet discovered that the Apache mod_session module\n incorrectly handled certain SessionHeader values. A remote attacker could\n use this issue to cause Apache to crash, resulting in a denial of service,\n or possibly execute arbitrary code. (CVE-2021-26691)\n\n Christoph Anton Mitterer discovered that the new MergeSlashes configuration\n option resulted in unexpected behaviour in certain situations.\n (CVE-2021-30641)","dates":{"published":"2021-06-21T15:25:05.000Z","modified":"2026-06-29T13:49:26.442Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":null,"severity":"unknown","version":null,"versionLabel":null,"source":null,"vector":null,"computed":false,"selection":"none"},"metrics":[]},"epss":{"probability":null,"percentile":null,"severity":"unknown","asOf":null,"change":{"pp":null,"baselineDate":null,"baselineScore":null},"history":[],"last30":[]},"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":[],"exploitCount":0,"weaknesses":[],"affected":[{"vendor":"ubuntu","product":"apache2","name":"apache2","label":"apache2","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/apache2","purlType":"deb","versions":[{"text":"< 2.4.7-1ubuntu4.22+esm1","noFixRecorded":false,"fixedIn":null},{"text":"< 2.4.18-2ubuntu3.17+esm1","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 2.4.7-1ubuntu4.22+esm1 | < 2.4.18-2ubuntu3.17+esm1","eol":null,"hubHref":null}],"affectedCount":1,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://ubuntu.com/security/notices/USN-4994-2","label":"ubuntu.com/security/notices/USN-4994-2","hostname":"ubuntu.com","tags":["Advisory"]},{"url":"https://ubuntu.com/security/CVE-2020-35452","label":"ubuntu.com/security/CVE-2020-35452","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/CVE-2021-26690","label":"ubuntu.com/security/CVE-2021-26690","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/CVE-2021-26691","label":"ubuntu.com/security/CVE-2021-26691","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/CVE-2021-30641","label":"ubuntu.com/security/CVE-2021-30641","hostname":"ubuntu.com","tags":["REPORT"]}],"lineage":{"upstream":["CVE-2020-35452","CVE-2021-26690","CVE-2021-26691","CVE-2021-30641"],"downstream":[],"duplicates":[],"related":["CVE-2020-35452","CVE-2021-26690","CVE-2021-26691","CVE-2021-30641"]},"timeline":[{"kind":"published","date":"2021-06-21T15:25:05.000Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-06-29T13:49:26.442Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":0,"level":"minimal","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-19T06:17:55.074Z","stale":false,"partial":false}}