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CVE-2026-11812— UpdateHub: race condition on shared context causes out-of-bounds write and DoS

Quick assessment

Affected
zephyrproject zephyr
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

zephyrproject zephyr是zephyrproject组织开源的一个面向物联网设备的实时操作系统。 zephyrproject zephyr 2.0.0版本至4.4.1版本存在竞争条件问题漏洞，该漏洞源于对ctx访问未进行序列化，prepare_fds()函数写入ctx.fds时缺少边界检查，存在竞争条件，可能导致更新子系统内部状态损坏和固件更新路径拒绝服务。

CVSS 2.5 · Low EPSS 0.10% · P1

Possible ATT&CK Techniques 2 AI

T1562.001 T1564.004 · NTFS File Attributes

Affected Version Matrix 1

VendorProduct Version RangeStatus
zephyrproject zephyr 2.0.0< 4.4.2 affected
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I. Basic Information for CVE-2026-11812

Vulnerability Information
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Vulnerability Title
UpdateHub: race condition on shared context causes out-of-bounds write and DoS
Source: CVE Program / CVE List V5
Vulnerability 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().
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
使用共享资源的并发执行不恰当同步问题(竞争条件)
Source: CVE Program / CVE List V5
Vulnerability Title
zephyrproject zephyr 竞争条件问题漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
zephyrproject zephyr是zephyrproject组织开源的一个面向物联网设备的实时操作系统。 zephyrproject zephyr 2.0.0版本至4.4.1版本存在竞争条件问题漏洞，该漏洞源于对ctx访问未进行序列化，prepare_fds()函数写入ctx.fds时缺少边界检查，存在竞争条件，可能导致更新子系统内部状态损坏和固件更新路径拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
zephyrproject zephyr 2.0.0 ~ 4.4.2 -

II. Public POCs for CVE-2026-11812

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III. Intelligence Information for CVE-2026-11812

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Patches & Fixes for CVE-2026-11812 (1)

Vendor Advisories for CVE-2026-11812 (1)

Same Patch Batch · zephyrproject · 2026-08-10 · 5 CVEs total

CVE-2026-8718 8.4 HIGH Out-of-bounds write in DTLS peer Connection ID getsockopt (`TLS_DTLS_PEER_CID_VALUE`) in Z
CVE-2026-11810 7.5 HIGH NULL-pointer dereference in UpdateHub OTA agent on empty inner metadata array (remote DoS)
CVE-2026-11809 3.7 LOW UpdateHub probe: uninitialized-heap out-of-bounds read of network-supplied metadata
CVE-2026-11811 3.7 LOW Socket file-descriptor leak in UpdateHub OTA client start_coap_client() leading to resourc

IV. Related Vulnerabilities

Same product: zephyr
Same vendor: zephyrproject
Same weakness: CWE-362

V. Comments for CVE-2026-11812

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