# CVE-2026-11809: UpdateHub probe: uninitialized-heap out-of-bounds read of network-supplied metadata

Status: published. Published: 2026-08-10. Updated: 2026-11-04.

The UpdateHub OTA client in subsys/mgmt/updatehub/updatehub.c contains an out-of-bounds / uninitialized-memory read in z_impl_updatehub_probe(). The probe response from the UpdateHub server is copied into a heap buffer (metadata) that is correctly NUL-terminated, but a second buffer (metadata_copy) is allocated with k_malloc (unzeroed) and filled with memcpy(metadata_copy, metadata, strlen(metadata)), which omits the terminating NUL. Everything after the copied content remains uninitialized heap.

When the first json_obj_parse() over the array descriptor fails, the code falls back to json_obj_parse(metadata_copy, strlen(metadata_copy), ...). The strlen() call scans past the copied bytes through uninitialized heap and, if no zero byte is found before the end of the allocation, reads beyond the buffer; the resulting over-long length is then parsed as JSON. The probe payload is fully controlled by the (malicious, compromised, or — without the optional CONFIG_UPDATEHUB_DTLS — on-path) UpdateHub server, which can craft a large payload that fails the first parse to drive this path.

The consequence is a read of uninitialized heap, with a worst case of an out-of-bounds read past the metadata_copy allocation that can fault and crash the update thread/device, producing a network-triggerable denial of service. The over-read data is consumed only internally to evaluate the update and is not returned to the attacker, so there is no direct information disclosure and no out-of-bounds write.

The fix zeroes metadata_copy with memset before the copy, guaranteeing NUL termination and bounding strlen() within the allocation.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: zephyr) — https://github.com/zephyrproject-rtos/zephyr/commit/69bbed5e601495a2076f25d822adbf991cae5c01

## Affected products and versions

- zephyrproject / zephyr (zephyr): ≥ 2.0.0; < 4.3.2 (affected, semver); ≥ 4.4.0; < 4.4.2 (affected, semver). Source: CNA: zephyr

## Severity and prioritization

- CVSS 3.1: 3.7 (low); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L; source: CNA: zephyr

- CVSS 3.1: 3.7 (low); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L; source: NVD: vulnerabilities@zephyrproject.org

- CISA KEV: No listing in collected sources

- EPSS: 0.35% as of 2026-11-03; percentile 29.07%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-125, CWE-908

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/zephyrproject-rtos/zephyr/commit/69bbed5e601495a2076f25d822adbf991cae5c01 (CNA: zephyr; patch)

- https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-6r86-hvv2-h6g4 (CNA: zephyr)

- https://github.com/zephyrproject-rtos/zephyr/commit/69bbed5e601495a2076f25d822adbf991cae5c01 (vulnerabilities@zephyrproject.org)

- https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-6r86-hvv2-h6g4 (vulnerabilities@zephyrproject.org)

## Provenance

- CNA: zephyr: https://www.cve.org/CVERecord?id=CVE-2026-11809; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-11809; retrieved 2026-11-04; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-11809; retrieved 2026-11-04; source updated Not reported

Revision: b08fcb61dc5fa599fd7756585c1bdac29912ace18cf635b374be4dbeff3ac717

Canonical: https://y2.dev/cve/CVE-2026-11809

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