VulnerabilityPublished 30 Jun 2026Updated 15 Oct 2026

CVE-2026-10654: zephyrproject zephyr · Race

Affects zephyrproject zephyrSource CVE Database V5

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Not known to be exploited · CVSS 3.1 Low : upgrade to 4.4.2 or 4.3.1 when convenient.

Data as of 13 Nov 2026, 23:53 UTC

CVSS 3.1 base score

3.1Low

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.4.2, 4.3.1

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

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

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Adjacent: The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 30 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade zephyrproject zephyr to 4.4.2 or 4.3.1.

Affected software

Product	Affected	Fixed in
zephyrprojectzephyr	Affected >=4.4.0 <4.4.2	Fixed in 4.4.2
zephyrprojectzephyr	Affected >=1.6.0 <4.3.1	Fixed in 4.3.1
GitHubzephyr`pkg:github/zephyr`Other threats	Affected >=1.6.0 <4.3.1 >=4.4.0 <4.4.2	Fixed in 4.3.1 4.4.2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

If you cannot patch yet, be aware that exploitation requires a complex timing race and impacts availability only. No other mitigation steps are explicitly provided.

Description

A race condition in the Zephyr Bluetooth Classic RFCOMM host stack (subsys/bluetooth/host/classic/rfcomm.c) mishandles a simultaneous bidirectional session disconnect. When the local device has initiated a session teardown (state BT_RFCOMM_STATE_DISCONNECTING, DISC sent, RTX timer armed) and the connected peer concurrently sends its own DISC frame for dlci 0, rfcomm_handle_disc() invokes rfcomm_session_disconnected(), which unconditionally forced the session to BT_RFCOMM_STATE_DISCONNECTED without ever calling bt_l2cap_chan_disconnect(). Because the recovery timer was also cancelled and a later UA is ignored in the DISCONNECTED state, the session becomes permanently wedged: the underlying L2CAP channel is never released and the session slot in the fixed bt_rfcomm_pool[CONFIG_BT_MAX_CONN] array is never reclaimed (its conn pointer stays set). Subsequent bt_rfcomm_dlc_connect() calls on that connection fail with -EINVAL due to the invalid session state, so RFCOMM service is denied for that peer, and repeated occurrences can exhaust the session pool. The DISC frame is peer-controlled over the air, but exploitation requires the peer's DISC to collide with a local-initiated disconnect (a high-complexity timing race). Impact is availability/resource-leak only; there is no memory-safety, confidentiality, or integrity consequence. The defect shipped in released versions (present in v4.4.0 and earlier). The fix only transitions to DISCONNECTED when the session is not already in DISCONNECTING, preserving the proper L2CAP teardown path.

Impact

The vulnerability causes a denial of service by wedging the RFCOMM session state and leaking session resources. This prevents new RFCOMM connections from being established with the affected peer and can exhaust the session pool. There are no impacts on confidentiality, integrity, or memory safety. Exploitation requires a precise timing race between local and peer disconnects.

Summary

The vulnerability is a race condition in Zephyr's Bluetooth Classic RFCOMM host stack (rfcomm.c) where concurrent disconnect requests from the local device and the peer cause improper session state handling. Specifically, if the local device initiates a disconnect and the peer simultaneously sends a DISC frame, the session state forcibly transitions to DISCONNECTED without properly disconnecting the underlying L2CAP channel. This leaves the session slot unreleased and the connection pointer set, causing subsequent connection attempts to fail and denying RFCOMM service. The defect is present in version 1.6.0 and earlier. The fix involves ensuring the session only transitions to DISCONNECTED if not already in DISCONNECTING, preserving correct L2CAP teardown.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 15 Jul 2026, 10:47 UTC

Technical details

References

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