{"schemaVersion":3,"id":"CVE-2026-90954","aliases":["DEBIAN-CVE-2026-90954","UBUNTU-CVE-2026-90954"],"status":"published","duplicateOf":null,"title":null,"description":"A flaw was found in BusyBox's dpkg-deb archive extraction. The ar archive handler flushes deferred symlinks after each archive member, unlike the tar, cpio, and unzip handlers which flush once after the last member. A specially crafted .deb archive with two data.tar members can exploit this ordering: the first member declares a symlink pointing to an absolute path (e.g., '/'), which is deferred as unsafe but flushed after the first member. The second member declares a regular file whose path traverses the now-live symlink, resulting in a file being written outside the intended extraction directory. This could allow an attacker to write arbitrary files to arbitrary locations when a user extracts a crafted .deb package.","dates":{"published":"2026-10-14T10:00:08.215Z","modified":"2026-10-19T19:04:36.467Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":7.8,"severity":"high","version":"3.1","versionLabel":"v3.1","source":"CVE.org","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":7.8,"severity":"high","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":7.8,"severity":"high","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"OSV · 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Ubuntu","score":7.8,"severity":"high","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","exploitability":4.6,"impact":9.8,"computed":true}]},"epss":{"probability":0.00197,"percentile":0.08856,"severity":"low","asOf":"2026-10-19T00:00:00.000Z","change":{"pp":null,"baselineDate":null,"baselineScore":null},"history":[{"date":"2026-10-14T00:00:00.000Z","score":0.00197,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00197,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00197,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00197,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00197,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00197,"percentile":0.08856}],"last30":[{"date":"2026-10-14T00:00:00.000Z","score":0.00197,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00197,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00197,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00197,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00197,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00197,"percentile":0.08856}]},"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-59","name":"Improper Link Resolution Before File Access ('Link Following')","description":"The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.","type":"weakness","status":"Draft","abstraction":"Base","likelihoodOfExploit":"Medium","url":"https://cwe.mitre.org/data/definitions/59.html"}],"affected":[{"vendor":"debian","product":"busybox","name":"busybox","label":"busybox","ecosystem":"Debian","cpePart":null,"purl":"pkg:deb/debian/busybox","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null}],"versionsText":"All versions (No fix recorded)","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"busybox","name":"busybox","label":"busybox","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/busybox","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null}],"versionsText":"All versions (No fix recorded)","eol":null,"hubHref":null}],"affectedCount":2,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-90954","label":"access.redhat.com/security/cve/CVE-2026-90954","hostname":"access.redhat.com","tags":["VDB Entry","X Refsource REDHAT","REPORT"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2533007","label":"bugzilla.redhat.com/show_bug.cgi?id=2533007","hostname":"bugzilla.redhat.com","tags":["Issue Tracking","X Refsource REDHAT","REPORT"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-90954","label":"security-tracker.debian.org/tracker/CVE-2026-90954","hostname":"security-tracker.debian.org","tags":["Advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-90954","label":"ubuntu.com/security/CVE-2026-90954","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-90954","label":"www.cve.org/CVERecord?id=CVE-2026-90954","hostname":"www.cve.org","tags":["REPORT"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2026-10-14T10:00:08.215Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-10-19T19:04:36.467Z","label":"Last modified","detail":"Vulnerability information 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