BT Mesh SDK: Improper Handling of Length Parameter Inconsistency
CVE-2026-5706 is a high-severity improper handling of length parameter inconsistency vulnerability in BT Mesh SDK from Silicon Labs, with a CVSS 4.0 base score of 8.9 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. Affected BT Mesh SDK versions: 6.1.4, 9.1.0 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.39% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of BT Mesh SDK you run against the affected versions below, and install the vendor's latest release.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Silicon Labs | BT Mesh SDK | 6.1.4, 9.1.0 and earlier | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- AdjacentThe attacker must be on the same local network segment.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Attack requirements
- PresentThe target must be in a specific state or configuration for the attack to work.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Confidentiality (vulnerable system)
- HighSerious loss of confidentiality on the vulnerable system.
- Integrity (vulnerable system)
- HighSerious loss of integrity on the vulnerable system.
- Availability (vulnerable system)
- HighSerious loss of availability on the vulnerable system.
- Confidentiality (other systems)
- LowLimited loss of confidentiality on systems beyond the vulnerable one.
- Integrity (other systems)
- LowLimited loss of integrity on systems beyond the vulnerable one.
- Availability (other systems)
- HighSerious loss of availability on systems beyond the vulnerable one.
Vector: CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA (silabs.com).
Official description
In Bluetooth Mesh SDK 6.1.4 and earlier, malformed extended advertisements can trigger out-of-bounds writes leading to stack corruption and remote code execution. These messages must come from a device that has already joined the network. Only provisioners supporting extended advertisements may be impacted.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Handling of Length Parameter Inconsistency
The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.
How developers prevent this class of flaw
- When processing structured incoming data containing a size field followed by raw data, ensure that you identify and resolve any inconsistencies between the size field and the actual size of the data.
- Do not let the user control the size of the buffer.
- Validate that the length of the user-supplied data is consistent with the buffer size.
More Improper Handling of Length Parameter Inconsistency vulnerabilities (CWE-130)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Recent Improper Handling of Length Parameter Inconsistency vulnerabilities
- 7.5 High severity
- 8.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 8.7 High severity
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