{"id":"UBUNTU-CVE-2025-34468","details":"libcoap versions up to and including 4.3.5, prior to commit 30db3ea, contain a stack-based buffer overflow in address resolution when attacker-controlled hostname data is copied into a fixed 256-byte stack buffer without proper bounds checking. A remote attacker can trigger a crash and potentially achieve remote code execution depending on compiler options and runtime memory protections. Exploitation requires the proxy logic to be enabled (i.e., the proxy request handling code path in an application using libcoap).","modified":"2026-05-20T16:21:24.319778318Z","published":"2025-12-31T19:15:00Z","upstream":["CVE-2025-34468"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2025-34468"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2025-34468"},{"type":"REPORT","url":"https://github.com/obgm/libcoap/pull/1737"},{"type":"REPORT","url":"https://github.com/obgm/libcoap/commit/30db3ea"},{"type":"REPORT","url":"https://libcoap.net/"},{"type":"REPORT","url":"https://www.vulncheck.com/advisories/libcoap-stack-based-buffer-overflow-in-address-resolution-dos-or-potential-rce"}],"affected":[{"package":{"name":"libcoap","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/libcoap?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.1.2-1"],"ecosystem_specific":{"binaries":[{"binary_name":"libcoap-1-0","binary_version":"4.1.2-1"},{"binary_version":"4.1.2-1","binary_name":"libcoap-1-0-bin"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-34468.json"}},{"package":{"name":"libcoap2","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/libcoap2?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.2.0-2","4.2.1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"libcoap2","binary_version":"4.2.1-1"},{"binary_version":"4.2.1-1","binary_name":"libcoap2-bin"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-34468.json"}},{"package":{"name":"libcoap2","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/libcoap2?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.2.1-1","4.2.1-1build1"],"ecosystem_specific":{"binaries":[{"binary_name":"libcoap2","binary_version":"4.2.1-1build1"},{"binary_version":"4.2.1-1build1","binary_name":"libcoap2-bin"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-34468.json"}},{"package":{"name":"libcoap3","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/libcoap3?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.3.0-2","4.3.0-2build1"],"ecosystem_specific":{"binaries":[{"binary_name":"libcoap3","binary_version":"4.3.0-2build1"},{"binary_name":"libcoap3-bin","binary_version":"4.3.0-2build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-34468.json"}},{"package":{"name":"libcoap3","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/libcoap3?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.3.1-2","4.3.3-1","4.3.4-1","4.3.4-1.1build2","4.3.4-1.1build3","4.3.4-1.1build4"],"ecosystem_specific":{"binaries":[{"binary_version":"4.3.4-1.1build4","binary_name":"libcoap3-bin"},{"binary_name":"libcoap3t64","binary_version":"4.3.4-1.1build4"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-34468.json"}},{"package":{"name":"libcoap3","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/libcoap3?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.3.4-1.1build4"],"ecosystem_specific":{"binaries":[{"binary_name":"libcoap3-bin","binary_version":"4.3.4-1.1build4"},{"binary_name":"libcoap3t64","binary_version":"4.3.4-1.1build4"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-34468.json"}},{"package":{"name":"libcoap3","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/libcoap3?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.3.4-1.1build4","4.3.5-1","4.3.5-2"],"ecosystem_specific":{"binaries":[{"binary_name":"libcoap3-bin","binary_version":"4.3.5-2"},{"binary_name":"libcoap3t64","binary_version":"4.3.5-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-34468.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},{"type":"Ubuntu","score":"medium"}]}