{"schemaVersion":3,"id":"CVE-2026-12852","aliases":["UBUNTU-CVE-2026-12852","DEBIAN-CVE-2026-12852"],"status":"published","duplicateOf":null,"title":null,"description":"In Bouncy Castle for Java before 1.85, MLS wire decoder allocates attacker-declared opaque length before bounds check.","dates":{"published":"2026-08-03T02:55:02.485Z","modified":"2026-08-03T15:11:39.086Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":8.7,"severity":"high","version":"4.0","versionLabel":"v4.0","source":"CVE.org","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/U:Amber","computed":false,"selection":"backend-summary"},"metrics":[{"version":"4.0","versionLabel":"v4.0","source":"CVE.org","score":8.7,"severity":"high","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/U:Amber","exploitability":null,"impact":null,"computed":false},{"version":"4.0","versionLabel":"v4.0","source":"OSV · Ubuntu","score":8.7,"severity":"high","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/U:Amber","exploitability":null,"impact":null,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Ubuntu","score":7.5,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","exploitability":10,"impact":6,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Debian","score":7.5,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","exploitability":10,"impact":6,"computed":true},{"version":"4.0","versionLabel":"v4.0","source":"NVD","score":8.7,"severity":"high","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Amber","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":7.5,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.0031,"percentile":0.2243,"severity":"low","asOf":"2026-10-19T00:00:00.000Z","change":{"pp":0,"baselineDate":"2026-09-19T00:00:00.000Z","baselineScore":0.0031},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.0031,"percentile":0.2243}],"last30":[{"date":"2026-09-19T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.0031,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.0031,"percentile":0.2243}]},"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":[{"id":"CWE-789","name":"Memory Allocation with Excessive Size Value","description":"The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.","type":"weakness","status":"Draft","abstraction":"Variant","likelihoodOfExploit":null,"url":"https://cwe.mitre.org/data/definitions/789.html"}],"affected":[{"vendor":"bouncycastle","product":"bc-java","name":"bc-java","label":"bc-java","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"< 1.85","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1.85","eol":null,"hubHref":"/vendor/bouncycastle/bc-java"},{"vendor":"debian","product":"bouncycastle","name":"bouncycastle","label":"bouncycastle","ecosystem":"Debian","cpePart":null,"purl":"pkg:deb/debian/bouncycastle","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null},{"text":"< 1.86-1","noFixRecorded":false,"fixedIn":null}],"versionsText":"All versions (No fix recorded) | < 1.86-1","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"bouncycastle","name":"bouncycastle","label":"bouncycastle","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/bouncycastle","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null}],"versionsText":"All versions (No fix recorded)","eol":null,"hubHref":null},{"vendor":"legion of the bouncy castle inc.","product":"bc-java","name":"BC-JAVA","label":"bc-java","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 1.73, < 1.85","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 1.73, < 1.85","eol":null,"hubHref":"/vendor/legion_of_the_bouncy_castle_inc/bc-java"}],"affectedCount":4,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9012852","label":"github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9012852","hostname":"github.com","tags":["Vendor Advisory","REPORT","Third Party Advisory"]},{"url":"https://github.com/bcgit/bc-java/commit/a747038bb5bbd5e29fb2b7607ab38af1fd8d1790","label":"github.com/bcgit/bc-java/commit/a747038bb5bbd5e29fb2b7607ab38af1fd8d1790","hostname":"github.com","tags":["Patch","REPORT"]},{"url":"https://ubuntu.com/security/CVE-2026-12852","label":"ubuntu.com/security/CVE-2026-12852","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-12852","label":"www.cve.org/CVERecord?id=CVE-2026-12852","hostname":"www.cve.org","tags":["REPORT"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-12852","label":"security-tracker.debian.org/tracker/CVE-2026-12852","hostname":"security-tracker.debian.org","tags":["Advisory"]}],"lineage":{"upstream":[],"downstream":["OPENSUSE-SU-2026:11445-1","OPENSUSE-SU-2026:21538-1","SUSE-SU-2026:23127-1","SUSE-SU-2026:23150-1","SUSE-SU-2026:3559-1"],"duplicates":[],"related":["OPENSUSE-SU-2026:11445-1","OPENSUSE-SU-2026:21538-1","SUSE-SU-2026:23127-1","SUSE-SU-2026:23150-1","SUSE-SU-2026:3559-1"]},"timeline":[{"kind":"published","date":"2026-08-03T02:55:02.485Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-08-03T15:11:39.086Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":35,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-19T23:30:15.247Z","stale":false,"partial":false}}