CVE-2026-10643— Out-of-bounds heap write in Zephyr `recvmsg()` ancillary-data path (`insert_pktinfo` undersizes the control-buffer capacity check)

Out-of-bounds heap write in Zephyr `recvmsg()` ancillary-data path (`insert_pktinfo` undersizes the control-buffer capacity check)

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 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. Under 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. The 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. The 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.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:H

跨界内存写

zephyr 缓冲区错误漏洞

Zephyr是Zephyr组织开源的一个可扩展的实时操作系统 (RTOS)。 Zephyr 3.6.0版本至4.4.0版本存在缓冲区错误漏洞，该漏洞源于IP socket recvmsg()实现中未正确验证用户提供的辅助缓冲区，导致固定大小的越界写入，可能造成内核堆内存损坏，攻击者可从无特权的用户空间线程触发该漏洞。

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