Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
zephyrproject zephyr — Out-of-bounds heap write in Zephyr `recvmsg()` ancillary-data path (`insert_pktinfo` undersizes the control-buffer capacity check)
AV AC PR UI S C I A CVSS EPSS %ile KEV
L L L N U H H H 7.8 .0013 2.6 —
AFFECTED
Product Versions Fixed
zephyr 4.0.0 – —
TIMELINE
Jun 2 Reserved by zephyr
Jun 27 Published (CNA: zephyr)
Aug 6 RESCORED — CVE-2026-10643 (zephyrproject zephyr). CVSS 8.7 → 7.8 (NVD).
Description
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.
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
|---|
| June 2, 2026 | Reserved | Reserved by zephyr |
| June 27, 2026 | Published | Published (CNA: zephyr) |
| August 6, 2026 | RESCORED | RESCORED — CVE-2026-10643 (zephyrproject zephyr). CVSS 8.7 → 7.8 (NVD). |
Affected
Affected products and packages — 1 row
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|
| zephyrproject | zephyr | — | 4.0.0 | — |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-10643 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.