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 read in DHCPv4 client message-type name lookup (net_dhcpv4_msg_type_name)
AV AC PR UI S C I A CVSS EPSS %ile KEV
A L N N U L N L 5.4 .0018 8.0 —
AFFECTED
Product Versions Fixed
zephyr 1.7.0 – —
TIMELINE
Jun 3 Reserved by zephyr
Aug 1 EXPLOIT PUBLISHED — CVE-2026-10773 (zephyrproject zephyr). Public exploit reference added.
Aug 1 Published (CNA: zephyr)
Aug 7 EXPLOIT PUBLISHED — CVE-2026-10773 (zephyrproject zephyr). Public exploit reference added.
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.
The 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.
The 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.
Lifecycle
Complete event history — 4 events, chronological
| Date | Event | Detail |
|---|
| June 3, 2026 | Reserved | Reserved by zephyr |
| August 1, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-10773 (zephyrproject zephyr). Public exploit reference added. |
| August 1, 2026 | Published | Published (CNA: zephyr) |
| August 7, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-10773 (zephyrproject zephyr). Public exploit reference added. |
Affected
Affected products and packages — 1 row
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|
| zephyrproject | zephyr | — | 1.7.0 | — |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-10773 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.