{"id":"CVE-2026-10773","state":"PUBLISHED","title":"Out-of-bounds read in DHCPv4 client message-type name lookup (net_dhcpv4_msg_type_name)","description":"The DHCPv4 client helper net_dhcpv4_msg_type_name() in subsys/net/lib/dhcpv4/dhcpv4.c indexes a static 8-element const char * name table after a faulty bounds check. The guard used msg_type <= sizeof(name) instead of msg_type <= ARRAY_SIZE(name); sizeof returns the byte size of the pointer array (32 on 32-bit, 64 on 64-bit targets) rather than the element count of 8, so message-type values from 9 up to that byte size pass the check and cause name[msg_type - 1] to read past the end of the array.\n\nThe msg_type value originates from the DHCP MESSAGE TYPE option, which is read as an unchecked raw byte from a received packet (net_pkt_read_u8) and passed unmodified into the lookup. A DHCP server, or any host able to inject a spoofed DHCP reply onto the client's link, can therefore drive the index out of bounds. The out-of-range slot yields a garbage const char * that is then dereferenced by a %s log conversion.\n\nThe lookup is reached only from a debug log statement (NET_DBG / LOG_DBG), so the out-of-bounds read is triggerable only when the DHCPv4 log module is built at DEBUG level (CONFIG_NET_DHCPV4_LOG_LEVEL_DBG), which is not the default configuration. When that condition holds, the result is an out-of-bounds read and a wild-pointer dereference: most likely a crash of the DHCP client (denial of service) and potentially disclosure of an adjacent pointer's contents through the log output. The fix replaces sizeof with ARRAY_SIZE, restoring the correct 1..8 acceptance window.","publishedAt":"2026-08-01T12:21:17.622Z","updatedAt":"2026-08-31T23:13:20.890Z","severity":{"score":5.4,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","source":"zephyr"},"assigner":"zephyr","products":["zephyrproject zephyr"],"affected":[{"vendor":"zephyrproject","product":"zephyr","packageName":"zephyr","defaultStatus":"unaffected","versions":[{"version":"1.7.0","status":"affected","lessThan":"4.4.2","versionType":"semver"}],"collectionURL":"https://github.com/zephyrproject-rtos/zephyr","programFiles":["subsys/net/lib/dhcpv4/dhcpv4.c","subsys/net/lib/dhcpv6/dhcpv6.c"]}],"references":["https://github.com/zephyrproject-rtos/zephyr/commit/73c8a7df4f00088fc04ee5ab71bcabf47fcd3db7","https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-r5hq-xq42-wcfq"],"weaknesses":["CWE-125","CWE-682"],"ingestedAt":"2026-10-29T20:10:33.477Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/10xxx/CVE-2026-10773.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-10773","state":"PUBLISHED","datePublished":"2026-08-01T12:21:17.622Z","dateUpdated":"2026-08-31T23:13:20.890Z","assignerShortName":"zephyr","assignerOrgId":"e2e69745-5e70-4e92-8431-deb5529a81ad","dateReserved":"2026-06-03T15:44:06.548Z"},"containers":{"cna":{"title":"Out-of-bounds read in DHCPv4 client message-type name lookup (net_dhcpv4_msg_type_name)","descriptions":[{"lang":"en","value":"The DHCPv4 client helper net_dhcpv4_msg_type_name() in subsys/net/lib/dhcpv4/dhcpv4.c indexes a static 8-element const char * name table after a faulty bounds check. The guard used msg_type <= sizeof(name) instead of msg_type <= ARRAY_SIZE(name); sizeof returns the byte size of the pointer array (32 on 32-bit, 64 on 64-bit targets) rather than the element count of 8, so message-type values from 9 up to that byte size pass the check and cause name[msg_type - 1] to read past the end of the array.\n\nThe msg_type value originates from the DHCP MESSAGE TYPE option, which is read as an unchecked raw byte from a received packet (net_pkt_read_u8) and passed unmodified into the lookup. A DHCP server, or any host able to inject a spoofed DHCP reply onto the client's link, can therefore drive the index out of bounds. The out-of-range slot yields a garbage const char * that is then dereferenced by a %s log conversion.\n\nThe lookup is reached only from a debug log statement (NET_DBG / LOG_DBG), so the out-of-bounds read is triggerable only when the DHCPv4 log module is built at DEBUG level (CONFIG_NET_DHCPV4_LOG_LEVEL_DBG), which is not the default configuration. When that condition holds, the result is an out-of-bounds read and a wild-pointer dereference: most likely a crash of the DHCP client (denial of service) and potentially disclosure of an adjacent pointer's contents through the log output. The fix replaces sizeof with ARRAY_SIZE, restoring the correct 1..8 acceptance window."}],"affected":[{"vendor":"zephyrproject","product":"zephyr","packageName":"zephyr","defaultStatus":"unaffected","versions":[{"version":"1.7.0","status":"affected","lessThan":"4.4.2","versionType":"semver"}],"collectionURL":"https://github.com/zephyrproject-rtos/zephyr","programFiles":["subsys/net/lib/dhcpv4/dhcpv4.c","subsys/net/lib/dhcpv6/dhcpv6.c"]}],"references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/73c8a7df4f00088fc04ee5ab71bcabf47fcd3db7","name":"Fix commit","tags":["patch"]},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-r5hq-xq42-wcfq","name":"GHSA-r5hq-xq42-wcfq"}],"metrics":[{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","baseScore":5.4,"baseSeverity":"MEDIUM"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-125","lang":"en","description":"bounds","type":"CWE"},{"cweId":"CWE-682","lang":"en","description":"bounds","type":"CWE"}]}],"providerMetadata":{"shortName":"zephyr","orgId":"e2e69745-5e70-4e92-8431-deb5529a81ad","dateUpdated":"2026-08-31T23:13:20.890Z"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-r5hq-xq42-wcfq","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-03T17:50:29.274490Z","id":"CVE-2026-10773","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-03T17:50:55.197Z"}}]}}}