Answer in brief
CVE-2026-10648 records a Medium severity (CVSS 6.2) vulnerability in NULL-pointer dereference in MCUmgr serial/console SMP transport on buffer-pool exhaustion. The current sources do not mark it as known exploited. The current feed maps zephyrproject/zephyr (generic), zephyrproject/zephyr (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 6.2. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps zephyrproject/zephyr (generic), zephyrproject/zephyr (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:zephyrproject:zephyr:4.4.0:-:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:zephyrproject:zephyr:4.4.0:rc1:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:zephyrproject:zephyr:4.4.0:rc2:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:zephyrproject:zephyr:4.4.0:rc3:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| zephyrproject/zephyrgeneric | >=4.4.0 <4.5.0 | 4.5.0 |
| zephyrproject/zephyrgeneric | >=4.4.0 <4.4.1 | 4.4.1 |
Published upstream
Jun 29, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 4, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 30, 2026
mcumgr_serial_process_frag() in subsys/mgmt/mcumgr/transport/src/serial_util.c calls net_buf_reset() on the result of smp_packet_alloc() before checking it for NULL. smp_packet_alloc() uses net_buf_alloc(K_NO_WAIT) against the shared MCUmgr packet pool (CONFIG_MCUMGR_TRANSPORT_NETBUF_COUNT, default 4), which returns NULL when the pool is exhausted. In default builds the __ASSERT_NO_MSG in net_buf_reset is a no-op, so net_buf_simple_reset writes through the NULL pointer (buf->len = 0; buf->data = buf->__buf), causing a fault/crash. The fragment data reaches this code from attacker-controlled bytes on the MCUmgr serial/UART/shell-console transports (smp_uart.c, smp_raw_uart.c, smp_shell.c), and a fresh buffer is allocated at the start of essentially every new packet. An attacker on the serial/console link can flood the transport to drive the 4-entry buffer pool to exhaustion and induce the NULL dereference, crashing the device (denial of service). The defect was introduced after the original MCUmgr rework and shipped in Zephyr v4.4.0. The fix moves the NULL check ahead of net_buf_reset.
Quoted source text, attributed separately from HOL analysis.