CVE-2026-10658

CVE-2026-10658 is a high-severity vulnerability in Zephyrproject Zephyr with a CVSS 3.x base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.

Key facts

Description

A missing length validation in the Zephyr Bluetooth Host ISO receive path can be triggered by malformed HCI ISO data. In bt_iso_recv() (subsys/bluetooth/host/iso.c), when processing PB=START/SINGLE fragments, the code pulls a TS SDU header (8 bytes, ts=1) or a non-TS SDU header (4 bytes, ts=0) without first verifying that buf->len contains at least that many bytes. The outer HCI ISO length check in hci_iso() validates payload length consistency but not the minimum inner SDU header size, so a packet with payload length 1 passes hci_iso() and then reaches net_buf_pull_mem(), which asserts buf->len >= len. As a result, malformed ISO traffic deterministically triggers a kernel assert (denial of service) in assert-enabled builds, and in non-assert builds the same path may proceed with an undersized buffer, leading to out-of-bounds read behavior. The issue affects products using the Zephyr Host with CONFIG_BT_ISO_RX enabled, particularly where incoming HCI data can be influenced by a malicious or compromised controller or malformed forwarded ISO traffic.

Frequently asked questions

What is CVE-2026-10658?
A missing length validation in the Zephyr Bluetooth Host ISO receive path can be triggered by malformed HCI ISO data. In bt_iso_recv() (subsys/bluetooth/host/iso.c), when processing PB=START/SINGLE fragments, the code pulls a TS SDU header (8 bytes, ts=1) or a non-TS SDU header (4 bytes, ts=0) without first verifying that buf->len contains at least that many bytes. The outer HCI ISO length check in hci_iso() validates payload length consistency but not the minimum inner SDU header size, so a packet with payload length 1 passes hci_iso() and then reaches net_buf_pull_mem(), which asserts buf->len >= len. As a result, malformed ISO traffic deterministically triggers a kernel assert (denial of service) in assert-enabled builds, and in non-assert builds the same path may proceed with an undersized buffer, leading to out-of-bounds read behavior. The issue affects products using the Zephyr Host with CONFIG_BT_ISO_RX enabled, particularly where incoming HCI data can be influenced by a malicious or compromised controller or malformed forwarded ISO traffic.
How severe is CVE-2026-10658?
CVE-2026-10658 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability high.
Is CVE-2026-10658 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-10658?
CVE-2026-10658 affects Zephyrproject Zephyr. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-10658?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-10658 have an EU (EUVD) identifier?
Yes. CVE-2026-10658 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38410.
When was CVE-2026-10658 published?
CVE-2026-10658 was published on 2026-06-23 and last updated on 2026-07-06.

References

Affected products (1)

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