UpdateHub: race condition on shared context causes out-of-bounds write and DoS

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-11812
StatePUBLISHED
Assignerzephyr
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-10 23:16:51 UTC
Updated2026-08-12 19:17:29 UTC
DescriptionThe 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().

Risk And Classification

Primary CVSS: v3.1 2.5 LOW from [email protected]

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

EPSS: 0.000800000 probability, percentile 0.002160000 (date 2026-08-13)

Problem Types: CWE-362 | CWE-362 race

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary2.5LOWCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
3.1CNACVSS2.5LOWCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Zephyrproject Zephyr affected 2.0.0 4.4.1 semver Not specified

References

ReferenceSourceLinkTags
github.com/zephyrproject-rtos/zephyr/commit/551d3f92b36e9604f039101c4e4f... [email protected] github.com
github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-vprh-rff6-... [email protected] github.com
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