CVE-2019-9503

CVE-2019-9503 is a high-severity vulnerability in Broadcom Brcmfmac Driver with a CVSS 3.x base score of 7.9. 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-20.

Key facts

Description

The Broadcom brcmfmac WiFi driver prior to commit a4176ec356c73a46c07c181c6d04039fafa34a9f is vulnerable to a frame validation bypass. If the brcmfmac driver receives a firmware event frame from a remote source, the is_wlc_event_frame function will cause this frame to be discarded and unprocessed. If the driver receives the firmware event frame from the host, the appropriate handler is called. This frame validation can be bypassed if the bus used is USB (for instance by a wifi dongle). This can allow firmware event frames from a remote source to be processed. In the worst case scenario, by sending specially-crafted WiFi packets, a remote, unauthenticated attacker may be able to execute arbitrary code on a vulnerable system. More typically, this vulnerability will result in denial-of-service conditions.

Frequently asked questions

What is CVE-2019-9503?
The Broadcom brcmfmac WiFi driver prior to commit a4176ec356c73a46c07c181c6d04039fafa34a9f is vulnerable to a frame validation bypass. If the brcmfmac driver receives a firmware event frame from a remote source, the is_wlc_event_frame function will cause this frame to be discarded and unprocessed. If the driver receives the firmware event frame from the host, the appropriate handler is called. This frame validation can be bypassed if the bus used is USB (for instance by a wifi dongle). This can allow firmware event frames from a remote source to be processed. In the worst case scenario, by sending specially-crafted WiFi packets, a remote, unauthenticated attacker may be able to execute arbitrary code on a vulnerable system. More typically, this vulnerability will result in denial-of-service conditions.
How severe is CVE-2019-9503?
CVE-2019-9503 has a CVSS 3.x base score of 7.9, rated high severity. It is exploitable over an adjacent network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2019-9503 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-9503?
CVE-2019-9503 primarily affects Broadcom Brcmfmac Driver. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-9503?
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.
When was CVE-2019-9503 published?
CVE-2019-9503 was published on 2020-01-16 and last updated on 2026-06-17.

References

Affected products (3)

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