CVE-2025-39863 Vulnerability Analysis & Exploit Details

CVE-2025-39863
Vulnerability Scoring

Analysis In Progress
Analysis In Progress

Attack Complexity Details

  • Attack Complexity:
    Attack Complexity Analysis In Progress
  • Attack Vector:
    Attack Vector Under Analysis
  • Privileges Required: None
    No authentication is required for exploitation.
  • Scope:
    Impact is confined to the initially vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2025-39863 Details

Status: Received on 19 Sep 2025, 16:15 UTC

Published on: 19 Sep 2025, 16:15 UTC

CVSS Release:

CVE-2025-39863 Vulnerability Summary

CVE-2025-39863: In the Linux kernel, the following vulnerability has been resolved: wifi: brcmfmac: fix use-after-free when rescheduling brcmf_btcoex_info work The brcmf_btcoex_detach() only shuts down the btcoex timer, if the flag timer_on is false. However, the brcmf_btcoex_timerfunc(), which runs as timer handler, sets timer_on to false. This creates critical race conditions: 1.If brcmf_btcoex_detach() is called while brcmf_btcoex_timerfunc() is executing, it may observe timer_on as false and skip the call to timer_shutdown_sync(). 2.The brcmf_btcoex_timerfunc() may then reschedule the brcmf_btcoex_info worker after the cancel_work_sync() has been executed, resulting in use-after-free bugs. The use-after-free bugs occur in two distinct scenarios, depending on the timing of when the brcmf_btcoex_info struct is freed relative to the execution of its worker thread. Scenario 1: Freed before the worker is scheduled The brcmf_btcoex_info is deallocated before the worker is scheduled. A race condition can occur when schedule_work(&bt_local->work) is called after the target memory has been freed. The sequence of events is detailed below: CPU0 | CPU1 brcmf_btcoex_detach | brcmf_btcoex_timerfunc | bt_local->timer_on = false; if (cfg->btcoex->timer_on) | ... | cancel_work_sync(); | ... | kfree(cfg->btcoex); // FREE | | schedule_work(&bt_local->work); // USE Scenario 2: Freed after the worker is scheduled The brcmf_btcoex_info is freed after the worker has been scheduled but before or during its execution. In this case, statements within the brcmf_btcoex_handler() — such as the container_of macro and subsequent dereferences of the brcmf_btcoex_info object will cause a use-after-free access. The following timeline illustrates this scenario: CPU0 | CPU1 brcmf_btcoex_detach | brcmf_btcoex_timerfunc | bt_local->timer_on = false; if (cfg->btcoex->timer_on) | ... | cancel_work_sync(); | ... | schedule_work(); // Reschedule | kfree(cfg->btcoex); // FREE | brcmf_btcoex_handler() // Worker /* | btci = container_of(....); // USE The kfree() above could | ... also occur at any point | btci-> // USE during the worker's execution| */ | To resolve the race conditions, drop the conditional check and call timer_shutdown_sync() directly. It can deactivate the timer reliably, regardless of its current state. Once stopped, the timer_on state is then set to false.

Assessing the Risk of CVE-2025-39863

Access Complexity Graph

The exploitability of CVE-2025-39863 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2025-39863

No exploitability data is available for CVE-2025-39863.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2025-39863, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2025-39863, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2025-39863 does not compromise confidentiality.
  • Integrity: None
    CVE-2025-39863 does not impact data integrity.
  • Availability: None
    CVE-2025-39863 does not affect system availability.

CVE-2025-39863 References

External References

CWE Common Weakness Enumeration

Unknown

Protect Your Infrastructure against CVE-2025-39863: Combat Critical CVE Threats

Stay updated with real-time CVE vulnerabilities and take action to secure your systems. Enhance your cybersecurity posture with the latest threat intelligence and mitigation techniques. Develop the skills necessary to defend against CVEs and secure critical infrastructures. Join the top cybersecurity professionals safeguarding today's infrastructures.

Other 5 Recently Published CVEs Vulnerabilities

  • CVE-2025-43803 – Insecure direct object reference (IDOR) vulnerability in the Contacts Center widget in Liferay Portal 7.4.0 through 7.4.3.119, and older unsupporte...
  • CVE-2025-34206 – Vasion Print (formerly PrinterLogic) Virtual Appliance Host and Application (VA and SaaS deployments) mount host configuration and secret material ...
  • CVE-2025-34205 – Vasion Print (formerly PrinterLogic) Virtual Appliance Host versions prior to 22.0.843 and Application prior to 20.0.1923 (VA and SaaS deployments)...
  • CVE-2025-34204 – Vasion Print (formerly PrinterLogic) Virtual Appliance Host and Application (VA and SaaS deployments) contains multiple Docker containers that run ...
  • CVE-2025-34203 – Vasion Print (formerly PrinterLogic) Virtual Appliance Host versions prior to 22.0.1002 and Application versions prior to 20.0.2614 (VA and SaaS de...