Heap memory leak in mcumgr settings-management handlers on access-hook rejection leads to denial of service

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-15892
StatePUBLISHED
Assignerzephyr
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-13 23:16:28 UTC
Updated2026-09-13 23:16:28 UTC
DescriptionThe mcumgr SMP settings-management group handlers settings_mgmt_read(), settings_mgmt_write(), and settings_mgmt_delete() in subsys/mgmt/mcumgr/grp/settings_mgmt/src/settings_mgmt.c allocate a key_name buffer (and, for read, a data buffer) via k_malloc() when CONFIG_MCUMGR_GRP_SETTINGS_BUFFER_TYPE_HEAP is enabled, relying on the end: label to k_free() them. When CONFIG_MCUMGR_GRP_SETTINGS_ACCESS_HOOK is also enabled and the application access hook rejects a request by returning status MGMT_CB_ERROR_RC, the handler executed return ret_rc; directly, bypassing end: and leaking the heap allocation on every rejected request. The settings handlers are reachable over the unauthenticated SMP transport (Bluetooth LE, UART, or UDP, depending on product configuration). The access hook is the mechanism applications use to deny unauthorized settings access, and MGMT_CB_ERROR_RC is a common rejection style, so an attacker who can send settings read/write/delete commands that the hook rejects triggers a heap leak on each attempt. Because the leaked memory is never reclaimed until reboot, a sustained stream of rejected requests monotonically exhausts the kernel heap until k_malloc() fails, denying mcumgr service and impacting any other heap consumer on the device — a denial of service. The impact is availability-only; there is no memory corruption or information disclosure. Only configurations that select the heap buffer type, enable the access hook, and register a hook that returns MGMT_CB_ERROR_RC are affected (the default stack buffer type cannot leak).

Risk And Classification

Primary CVSS: v3.1 5.3 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Problem Types: CWE-401 | CWE-401 dos

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
3.1CNACVSS5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Zephyrproject Zephyr affected 3.5.0 4.4.2 semver Not specified

References

ReferenceSourceLinkTags
github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-rq68-wgv4-... [email protected] github.com
github.com/zephyrproject-rtos/zephyr/commit/fabc488d5b44143e5bd70dd37318... [email protected] github.com
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