CVE-2024-48981

CVE-2024-48981 is a high-severity vulnerability in Arm Mbed with a CVSS 3.x base score of 7.5. 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-120.

Key facts

Description

An issue was discovered in MBed OS 6.16.0. During processing of HCI packets, the software dynamically determines the length of the packet header by looking up the identifying first byte and matching it against a table of possible lengths. The initial parsing function, hciTrSerialRxIncoming does not drop packets with invalid identifiers but also does not set a safe default for the length of unknown packets' headers, leading to a buffer overflow. This can be leveraged into an arbitrary write by an attacker. It is possible to overwrite the pointer to a not-yet-allocated buffer that is supposed to receive the contents of the packet body. One can then overwrite the state variable used by the function to determine which state of packet parsing is currently occurring. Because the buffer is allocated when the last byte of the header has been copied, the combination of having a bad header length variable that will never match the counter variable and being able to overwrite the state variable with the resulting buffer overflow can be used to advance the function to the next step while skipping the buffer allocation and resulting pointer write. The next 16 bytes from the packet body are then written wherever the corrupted data pointer is pointing.

Frequently asked questions

What is CVE-2024-48981?
An issue was discovered in MBed OS 6.16.0. During processing of HCI packets, the software dynamically determines the length of the packet header by looking up the identifying first byte and matching it against a table of possible lengths. The initial parsing function, hciTrSerialRxIncoming does not drop packets with invalid identifiers but also does not set a safe default for the length of unknown packets' headers, leading to a buffer overflow. This can be leveraged into an arbitrary write by an attacker. It is possible to overwrite the pointer to a not-yet-allocated buffer that is supposed to receive the contents of the packet body. One can then overwrite the state variable used by the function to determine which state of packet parsing is currently occurring. Because the buffer is allocated when the last byte of the header has been copied, the combination of having a bad header length variable that will never match the counter variable and being able to overwrite the state variable with the resulting buffer overflow can be used to advance the function to the next step while skipping the buffer allocation and resulting pointer write. The next 16 bytes from the packet body are then written wherever the corrupted data pointer is pointing.
How severe is CVE-2024-48981?
CVE-2024-48981 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2024-48981 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-48981?
CVE-2024-48981 affects Arm Mbed. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2024-48981?
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.
Does CVE-2024-48981 have an EU (EUVD) identifier?
Yes. CVE-2024-48981 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-43187.
When was CVE-2024-48981 published?
CVE-2024-48981 was published on 2024-11-20 and last updated on 2026-06-17.

References

Affected products (1)

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