CVE-2026-10648

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.5 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 95% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
25(Track)
EG Risk 25/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity55% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
5%
KEV
Not listed

Published

June 29, 2026

Last Modified

July 14, 2026

Advisory Details (2)

Auto-updated Jun 30, 2026
Patch available. Sources: github_commit, github.
github Patch Available

NULL-pointer dereference in MCUmgr serial/console SMP transport on buffer-pool exhaustion · Advisory · zephyrproject-rtos/zephyr · GitHub

https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-j64f-h3ww-f32c
github_commit

commit 6f363ec6f7fd (zephyrproject-rtos/zephyr)

Fix landed in zephyrproject-rtos/zephyr commit 6f363ec6f7fd — awaiting tagged release

https://github.com/zephyrproject-rtos/zephyr/commit/6f363ec6f7fd6ae9ed7ca2ae66fd9c82dce31c59

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 13× in last 7d / 35× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-31 07:01 UTCEG score recompute
  2. 2026-07-30 16:27 UTCEPSS rescore
  3. 2026-07-30 08:46 UTCEG score recompute
  4. 2026-07-30 01:30 UTCEPSS rescore
  5. 2026-07-29 08:45 UTCEG score recompute
  6. 2026-07-28 15:36 UTCEPSS rescore
  7. 2026-07-28 10:16 UTCEG score recompute
  8. 2026-07-27 14:13 UTCEPSS rescore
  9. 2026-07-27 12:05 UTCEG score recompute
  10. 2026-07-26 14:54 UTCEPSS rescore
  11. 2026-07-26 14:54 UTCEPSS rescore
  12. 2026-07-26 13:57 UTCEG score recompute
  13. 2026-07-25 14:17 UTCEPSS rescore
  14. 2026-07-24 14:17 UTCEPSS rescore
  15. 2026-07-23 03:04 UTCEG score recompute
  16. 2026-07-22 14:08 UTCEPSS rescore
  17. 2026-07-20 17:08 UTCEPSS rescore
  18. 2026-07-19 14:30 UTCEPSS rescore
  19. 2026-07-18 10:04 UTCEPSS rescore
  20. 2026-07-16 17:02 UTCEPSS rescore
  21. 2026-07-15 16:57 UTCEPSS rescore
  22. 2026-07-14 19:21 UTCNVD updateCVSS v3 → 5.5
  23. 2026-07-14 19:00 UTCMITRE cvelistV5CVSS v3 → 6.2
  24. 2026-07-13 22:30 UTCEPSS rescore
  25. 2026-07-12 05:46 UTCEPSS rescore
Show 15 more
  1. 2026-07-09 19:10 UTCEPSS rescore
  2. 2026-07-08 15:15 UTCEPSS rescore
  3. 2026-07-08 15:15 UTCEPSS rescore
  4. 2026-07-07 13:46 UTCEPSS rescore
  5. 2026-07-06 02:23 UTCEPSS rescore
  6. 2026-07-05 02:30 UTCEPSS rescore
  7. 2026-07-05 02:30 UTCEPSS rescore
  8. 2026-07-04 06:31 UTCEPSS rescore
  9. 2026-07-02 17:39 UTCEG score recompute▼ 0.70
  10. 2026-07-02 01:21 UTCNVD updateCVSS v3 → 5.5
  11. 2026-07-01 15:06 UTCEPSS rescore
  12. 2026-07-01 15:06 UTCEPSS rescore
  13. 2026-06-30 23:22 UTCEPSS rescore
  14. 2026-06-29 23:14 UTCEG score recompute
  15. 2026-06-29 23:13 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-10648?
CVE-2026-10648 is a medium vulnerability published on June 29, 2026. mcumgrserialprocessfrag() in subsys/mgmt/mcumgr/transport/src/serialutil.c calls netbufreset() on the result of smppacketalloc() before checking it for NULL. smppacketalloc() uses netbufalloc(KNOWAIT) against the shared MCUmgr packet pool (CONFIGMCUMGRTRANSPORTNETBUFCOUNT, default 4), which returns…
When was CVE-2026-10648 disclosed?
CVE-2026-10648 was first published in the National Vulnerability Database on June 29, 2026, with the most recent update on July 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-10648 actively exploited?
CVE-2026-10648 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 95.4% of all scored CVEs.
What is the CVSS score of CVE-2026-10648?
CVE-2026-10648 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-10648?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-10648, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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