CVE-2023-1901

Host crash via dangling semaphore reference reuse

Published Jul 10, 2023 · Updated Nov 7, 2024

Use-after-free in Zephyr RTOS 3.3 and earlier allows attackers controlling an HCI controller to crash the Bluetooth host layer. After bt_hci_cmd_send_sync returns, hci_cmd_done leaves cmd(buf)->sync pointing to its expired stack semaphore and passes it to k_sem_give when a duplicate completion event arrives. Control of the HCI controller and duplicate completion delivery are required; code execution depends on control of reclaimed stack data.

CVSS severity5.9
Medium
EPSS probability0.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Zephyr RTOS 3.3 and earlier allows attackers controlling an HCI controller to crash the Bluetooth host layer. After bt_hci_cmd_send_sync returns, hci_cmd_done leaves cmd(buf)->sync pointing to its expired stack semaphore and passes it to k_sem_give when a duplicate completion event arrives. Control of the HCI controller and duplicate completion delivery are required; code execution depends on control of reclaimed stack data.

The record

CVE
CVE-2023-1901
Published
Jul 10, 2023
Updated
Nov 7, 2024
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-787, CWE-121, CWE-672, T1499
Attack vector
adjacent
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 10, 2023CVE publishedPublication date reported by the CVE source.
  2. Nov 7, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=3.3
  2. Affected versionversion=* <=3.3

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=0 <=3.3; version=* <=3.3

Published CVSS scores

5.9Zephyr ProjectCVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H
8.0NIST NVDCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-121Stack-based Buffer Overflow
CWE-672Operation on a Resource after Expiration or Release
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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