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MbedOperating system · Arm

CVE-2024-48985

HIGH · 7.5 CVSS v3.1 Published 2024-11-20
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
An issue was discovered in MBed OS 6.16.0. During processing of HCI packets, the software dynamically determines the length of the packet data by reading 2 bytes from the packet data. A buffer is then allocated to contain the entire packet, the size of which is calculated as the length of the packet body determined earlier and the header length. If the allocate fails because the specified packet is too large, no exception handling occurs and hciTrSerialRxIncoming continues to write bytes into the 4-byte large temporary header buffer, leading to a buffer overflow. This can be leveraged into an arbitrary write by an attacker. It is possible to overwrite the pointer to the buffer that is supposed to receive the contents of the packet body but which couldn't be allocated. One can then overwrite the state variable used by the function to determine which step of the parsing process is currently being executed. This advances the function to the next state, where it proceeds to copy data to that arbitrary location. The packet body is then written wherever the corrupted data pointer is pointing.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-120

A fixed-size buffer is filled without checking the length of the incoming data, so it overflows into neighbouring memory. This is the classic overflow attackers use to overwrite return addresses and hijack execution. The fix is strict length checks and safe, bounded string and memory functions.

General guidance for the classic buffer overflow class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
MbedOperating system
Affected:= 6.16.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch github.com →
Recommended fix Moderate confidence
  1. Locate the file containing hciTrSerialRxIncoming function in the Mbed OS codebase
  2. Apply the changes from vendor patch PR #384 (https://github.com/mbed-ce/mbed-os/pull/384) which adds proper exception handling for failed buffer allocation
  3. Ensure the fix includes bounds checking on the packet length before buffer allocation
  4. Verify that when buffer allocation fails, the function properly returns error instead of continuing to write to temporary buffer
  5. Rebuild and test the firmware to confirm the buffer overflow is resolved

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-48985 in production — separate from our analysis above.

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What this is

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What belongs here
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