CVE-2026-10648
MEDIUM 6.2mcumgr_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.
No known exploitation, public exploit, or elevated probability at this time. Track for changes.
Exploitation likelihood
0.1%chance of exploitation in 30 days · 1st percentile
Impact if exploited
6.2CVSS 3.1 · MEDIUM
- ConfidentialityNone
- IntegrityNone
- AvailabilityHigh
What an attacker needs
- ⚠Access: Requires local access to the host
- ✓Privileges: No account or privileges required
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
- reference https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-j64f-h3ww-f32c
- github-search Search GitHub for public PoC repos
Test against your own equipment
curl -s https://vulnpedia.com/cve/CVE-2026-10648/poc.jsonMachine-readable PoC index for this CVE (for automation).Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-10648/poc.json
Weakness (CWE)
- CWE-476: memory-safety
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Known Affected Software Configurations
| Vendor | Product | Version range |
|---|---|---|
| Zephyrproject | Zephyr | 4.4.0 |
| Zephyrproject | Zephyr | 4.4.0 |
| Zephyrproject | Zephyr | 4.4.0 |
| Zephyrproject | Zephyr | 4.4.0 |
All CVSS metrics
- MEDIUM 6.2 v3.1 · CNA Primary
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - MEDIUM 6.2 v3.1 · NVD Secondary
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - MEDIUM 5.5 v3.1 · NVD Primary
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H