{"id":"CVE-2026-124740","aliases":["EUVD-2026-123358","GHSA-9f82-ccff-m2qq","UBUNTU-CVE-2026-124740"],"status":"published","title":"Busybox: use-after-free of requested_ipv6 in udhcpc6","description":"A flaw was found in BusyBox's udhcpc6 DHCPv6 client. A malicious server on the local network can trigger a use-after-free condition by responding with a crafted Dynamic Host Configuration Protocol for IPv6 (DHCPv6) reply packet lacking usable address options. This issue causes the client to read stale heap memory, which can result in a Denial of Service (DoS) due to an application crash or disclose previously assigned network address data in subsequent discovery requests.","severity":{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-13","score":0.00203,"percentile":0.10348,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-416"],"published":"2026-11-11T11:19:51Z","modified":"2026-11-13T21:05:18Z","affected":[{"source":"osv","ecosystem":"Ubuntu:Pro:14.04:LTS","package":"busybox","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:1.20.0-8.1ubuntu1","1:1.20.0-9ubuntu1","1:1.20.0-9ubuntu2","1:1.21.0-1ubuntu1","1:1.21.0-1ubuntu1.4","1:1.21.0-1ubuntu1.4+esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:16.04:LTS","package":"busybox","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:1.22.0-15ubuntu1","1:1.22.0-15ubuntu1.4","1:1.22.0-15ubuntu1.4+esm1","1:1.22.0-15ubuntu1.4+esm2"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"busybox","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:1.22.0-19ubuntu2","1:1.27.2-1ubuntu3","1:1.27.2-1ubuntu4","1:1.27.2-2ubuntu2","1:1.27.2-2ubuntu3","1:1.27.2-2ubuntu3.1","1:1.27.2-2ubuntu3.2","1:1.27.2-2ubuntu3.3","1:1.27.2-2ubuntu3.4","1:1.27.2-2ubuntu3.4+esm1"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"busybox","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:1.30.1-4ubuntu4","1:1.30.1-4ubuntu5","1:1.30.1-4ubuntu6","1:1.30.1-4ubuntu6.1","1:1.30.1-4ubuntu6.2","1:1.30.1-4ubuntu6.3","1:1.30.1-4ubuntu6.4","1:1.30.1-4ubuntu6.5"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"busybox","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:1.30.1-6ubuntu3","1:1.30.1-7ubuntu1","1:1.30.1-7ubuntu2","1:1.30.1-7ubuntu3","1:1.30.1-7ubuntu3.1"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"busybox","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:1.36.1-3ubuntu1","1:1.36.1-6ubuntu1","1:1.36.1-6ubuntu3","1:1.36.1-6ubuntu3.1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"busybox","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:1.37.0-7ubuntu1","1:1.37.0-10.1ubuntu2","1:1.37.0-10.1ubuntu3","1:1.38.0-3ubuntu1","1:1.38.0-3ubuntu3","1:1.38.0-3ubuntu4"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"busybox","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:1.37.0-4ubuntu1","1:1.37.0-7ubuntu1"]}],"products":[{"vendor":"red hat","product":"red hat enterprise linux 6"},{"vendor":"red hat","product":"red hat hardened images"}],"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-124740","tags":["vdb-entry","x_refsource_REDHAT","report"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2571616","tags":["issue-tracking","x_refsource_REDHAT","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-124740"},{"url":"https://github.com/advisories/GHSA-9f82-ccff-m2qq"},{"url":"https://ubuntu.com/security/CVE-2026-124740","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-124740","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-124740","title":"Busybox: use-after-free of requested_ipv6 in udhcpc6","description":"A flaw was found in BusyBox's udhcpc6 DHCPv6 client. A malicious server on the local network can trigger a use-after-free condition by responding with a crafted Dynamic Host Configuration Protocol for IPv6 (DHCPv6) reply packet lacking usable address options. This issue causes the client to read stale heap memory, which can result in a Denial of Service (DoS) due to an application crash or disclose previously assigned network address data in subsequent discovery requests.","status":"published","published":"2026-11-11T11:19:51.92Z","modified":"2026-11-12T19:34:06.974Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"cna"}],"cwes":["CWE-416"],"updated_at":"2026-11-11T12:57:44.071307Z"}],"euvd":[{"id":"EUVD-2026-123358","description":"A flaw was found in BusyBox's udhcpc6 DHCPv6 client. A malicious server on the local network can trigger a use-after-free condition by responding with a crafted Dynamic Host Configuration Protocol for IPv6 (DHCPv6) reply packet lacking usable address options. This issue causes the client to read stale heap memory, which can result in a Denial of Service (DoS) due to an application crash or disclose previously assigned network address data in subsequent discovery requests.","status":"published","published":"2026-11-11T11:19:51Z","modified":"2026-11-12T19:34:06Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-11T14:29:04.585574Z"}],"ghsa":[{"id":"GHSA-9f82-ccff-m2qq","title":"A flaw was found in BusyBox's udhcpc6 DHCPv6 client. A malicious server on the local network can...","description":"A flaw was found in BusyBox's udhcpc6 DHCPv6 client. A malicious server on the local network can trigger a use-after-free condition by responding with a crafted Dynamic Host Configuration Protocol for IPv6 (DHCPv6) reply packet lacking usable address options. This issue causes the client to read stale heap memory, which can result in a Denial of Service (DoS) due to an application crash or disclose previously assigned network address data in subsequent discovery requests.","status":"published","published":"2026-11-11T12:31:41Z","modified":"2026-11-11T12:31:48Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"cwes":["CWE-416"],"updated_at":"2026-11-11T12:34:05.637143Z"}],"nvd":[{"id":"CVE-2026-124740","description":"A flaw was found in BusyBox's udhcpc6 DHCPv6 client. A malicious server on the local network can trigger a use-after-free condition by responding with a crafted Dynamic Host Configuration Protocol for IPv6 (DHCPv6) reply packet lacking usable address options. This issue causes the client to read stale heap memory, which can result in a Denial of Service (DoS) due to an application crash or disclose previously assigned network address data in subsequent discovery requests.","status":"published","published":"2026-11-11T12:19:47.71Z","modified":"2026-11-12T20:18:30.007Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"secondary"}],"cwes":["CWE-416"],"updated_at":"2026-11-12T21:32:44.319228Z"}],"osv":[{"id":"UBUNTU-CVE-2026-124740","description":"A flaw was found in BusyBox's udhcpc6 DHCPv6 client. A malicious server on the local network can trigger a use-after-free condition by responding with a crafted Dynamic Host Configuration Protocol for IPv6 (DHCPv6) reply packet lacking usable address options. This issue causes the client to read stale heap memory, which can result in a Denial of Service (DoS) due to an application crash or disclose previously assigned network address data in subsequent discovery requests.","status":"published","published":"2026-11-13T00:00:00Z","modified":"2026-11-13T21:05:18.714946314Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-13T21:30:20.292037Z"}]}}