Summary
In the Linux kernel, the following vulnerability has been resolved: wifi: brcmfmac: fix NULL...
In the Linux kernel, the following vulnerability has been resolved:
wifi: brcmfmac: fix NULL pointer dereference in brcmf_txfinalize()
On removal of the device or unloading of the kernel module a potential NULL
pointer dereference occurs.
The following sequence deletes the interface:
brcmf_detach()
brcmf_remove_interface()
brcmf_del_if()
Inside the brcmf_del_if() function the drvr->if2bss[ifidx] is updated to
BRCMF_BSSIDX_INVALID (-1) if the bsscfgidx matches.
After brcmf_remove_interface() call the brcmf_proto_detach() function is
called providing the following sequence:
brcmf_detach()
brcmf_proto_detach()
brcmf_proto_msgbuf_detach()
brcmf_flowring_detach()
brcmf_msgbuf_delete_flowring()
brcmf_msgbuf_remove_flowring()
brcmf_flowring_delete()
brcmf_get_ifp()
brcmf_txfinalize()
Since brcmf_get_ip() can and actually will return NULL in this case the
call to brcmf_txfinalize() will result in a NULL pointer dereference inside
brcmf_txfinalize() when trying to update ifp->ndev->stats.tx_errors.
This will only happen if a flowring still has an skb.
Although the NULL pointer dereference has only been seen when trying to
update the tx statistic, all other uses of the ifp pointer have been
guarded as well with an early return if ifp is NULL.
Impact
The application dereferences a null pointer, causing a crash. Typical impact: denial of service via crash.
CVE-2025-21744 has a CVSS score of 5.5 (Medium). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2025-21744? CVE-2025-21744 is a medium-severity null pointer dereference vulnerability. No fixed version is listed yet. The application dereferences a null pointer, causing a crash.
- How severe is CVE-2025-21744? CVE-2025-21744 has a CVSS score of 5.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Is there a fix for CVE-2025-21744? No fixed version is listed for CVE-2025-21744 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2025-21744 exploitable, and should I be worried? Whether CVE-2025-21744 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-21744 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.