Two independent paths mutate ctx concurrently: the background autohandler running on the system workqueue, and user-triggered operations reached through the updatehub run shell command, direct API calls, or — since the operations are exposed as syscalls — userspace threads. When a second flow enters prepare_fds() while ctx.nfds is already 1, the write lands one element past the array; by struct layout it overlaps the adjacent ctx.sock/ctx.nfds members. More broadly, the unsynchronized sharing lets two flows interleave connection setup and teardown, double-closing a socket descriptor or scribbling the shared buffers.
The result is corruption of the update subsystem's internal state and denial of service of the firmware-update path; the out-of-bounds write is contained within the ctx structure and there is no demonstrated path to memory outside it or to code execution. Triggering requires a local actor able to invoke update operations (or, with CONFIG_USERSPACE, an unprivileged userspace thread) and to win a timing race against the background handler; remote peers cannot control the race timing. The fix serializes the entry points with a mutex and adds a bounds check to prepare_fds().
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| zephyrproject | zephyr | unaffected |
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| Vendor | Product | Confidence | Versions | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Zephyrproject | Zephyr | 100% |
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Tracking
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Tue, 11 Aug 2026 02:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Zephyrproject
Zephyrproject zephyr |
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| Vendors & Products |
Zephyrproject
Zephyrproject zephyr |
Mon, 10 Aug 2026 23:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | The UpdateHub management subsystem (subsys/mgmt/updatehub/updatehub.c) drives every update operation through a single file-scope ctx structure that holds the CoAP block context, payload buffer, status code, socket, and a one-element poll-fd array fds[1]. Access to ctx was not serialized, and prepare_fds() wrote ctx.fds[ctx.nfds] and incremented ctx.nfds with no bounds check. Two independent paths mutate ctx concurrently: the background autohandler running on the system workqueue, and user-triggered operations reached through the updatehub run shell command, direct API calls, or — since the operations are exposed as syscalls — userspace threads. When a second flow enters prepare_fds() while ctx.nfds is already 1, the write lands one element past the array; by struct layout it overlaps the adjacent ctx.sock/ctx.nfds members. More broadly, the unsynchronized sharing lets two flows interleave connection setup and teardown, double-closing a socket descriptor or scribbling the shared buffers. The result is corruption of the update subsystem's internal state and denial of service of the firmware-update path; the out-of-bounds write is contained within the ctx structure and there is no demonstrated path to memory outside it or to code execution. Triggering requires a local actor able to invoke update operations (or, with CONFIG_USERSPACE, an unprivileged userspace thread) and to win a timing race against the background handler; remote peers cannot control the race timing. The fix serializes the entry points with a mutex and adds a bounds check to prepare_fds(). | |
| Title | UpdateHub: race condition on shared context causes out-of-bounds write and DoS | |
| Weaknesses | CWE-362 | |
| References |
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| Metrics |
cvssV3_1
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MITRE
Status: PUBLISHED
Assigner: zephyr
Published:
Updated: 2026-08-10T23:09:17.542Z
Reserved: 2026-06-09T15:51:50.979Z
Link: CVE-2026-11812
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-08-10T23:16:51.020
Modified: 2026-08-10T23:16:51.020
Link: CVE-2026-11812
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-08-11T01:45:06Z