{"id":"CVE-2026-10643","title":"Zephyr's IP socket recvmsg() implementation (subsys/net/lib/sockets/sockets_inet.c, insert_pktinfo()) validated the user-supplied ancillary (msg_control) buffer using only the payload length (msg->msg_controllen < pktinfo_len) before wri…","summary":"Zephyr's IP socket recvmsg() implementation (subsys/net/lib/sockets/sockets_inet.c, insert_pktinfo()) validated the user-supplied ancillary (msg_control) buffer using only the payload length (msg->msg_controllen < pktinfo_len) before wri…","severity":"high","cvss":8.7,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:H","cwe":["CWE-787"],"vendor":"zephyrproject","product":"zephyr","affected":["zephyr >= 3.6.0, <= 4.4.1"],"published":"2026-06-28","updated":"2026-08-06","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-10643","references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/01fe77b2ec3885583f709a17c5203ce02bd77012","label":"vulnerabilities@zephyrproject.org"},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-pvf7-7mrp-35w7","label":"vulnerabilities@zephyrproject.org"}],"tags":["nvd"],"epss":0.00164,"epssPercentile":0.05982,"ingestedAt":"2026-08-07T06:11:52.104Z","slug":"CVE-2026-10643","body":"## Overview\n\nZephyr's IP socket recvmsg() implementation (subsys/net/lib/sockets/sockets_inet.c, insert_pktinfo()) validated the user-supplied ancillary (msg_control) buffer using only the payload length (msg->msg_controllen < pktinfo_len) before writing a full control message consisting of an aligned cmsg header plus the payload. Because the check omitted the cmsg header size, a control buffer whose length falls in the under-checked window (e.g. 16-27 bytes for IPv4 IP_PKTINFO on a 64-bit target, where a single element actually occupies 28 bytes) passes the guard yet causes a fixed-size out-of-bounds write of up to one cmsg header (~12 bytes) past the end of the buffer.\n\nUnder CONFIG_USERSPACE the recvmsg verifier allocates a kernel-heap copy of the control buffer sized to msg_controllen and runs the implementation against it, so the overflow corrupts kernel heap memory and is triggerable from an unprivileged userspace thread; in supervisor mode it corrupts the caller's buffer.\n\nThe path is reachable on a UDP/IP socket with IP_PKTINFO/IPV6_RECVPKTINFO (or hoplimit/timestamping) enabled when the application calls recvmsg() with an undersized control buffer and a datagram is received; part of the overwritten bytes (the destination IP in ipi_addr) is influenced by the received packet.\n\nThe fix makes the capacity check use NET_CMSG_SPACE(pktinfo_len) (aligned header + aligned data) and returns -ENOMEM when the buffer is too small. Affected: v3.6.0 through v4.4.0.\n\n## Affected\n\n- `zephyr >= 3.6.0, <= 4.4.1`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":47.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}