Which versions of Silicon Labs Matter are affected by CVE-2026-6924?

Silicon Labs Matter implementation on SiWx917 devices generates predictable cryptographic material due to an entropy initialization bug, rendering all encrypted communications vulnerable to…. A patch is available.

How to fix or mitigate CVE-2026-6924?

Within 24 hours, conduct a comprehensive inventory of all SiWx917 devices with Matter implementation across your infrastructure, documenting firmware versions and deployment locations. Within 7 days, obtain and apply the available Silicon Labs patch to all identified devices following vendor update procedures for your deployment method (OTA, manual flashing, or distributor channels). Within 30 days, verify patch deployment across 100% of inventory through firmware verification, implement monitoring for exploitation attempts, and document all update actions for audit purposes.

Silicon Labs Matter CVE-2026-6924

Q: What is the CVSS score of CVE-2026-6924?

CVE-2026-6924 has a CVSS 4.0 base score of 8.7 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/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. EPSS exploitation probability: 0.3%.

EUVD-2026-48399 HIGH

Same Seed in Pseudo-Random Number Generator (PRNG) (CWE-336)

2026-07-23 Silabs

GHSA-wm5h-r2qh-r97h

Information Disclosure Silicon Labs Matter Github Silicon Labs

8.7

CVSS 4.0 · Vendor: Silabs

Severity by source

Vendor (Silabs) PRIMARY

8.7 HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/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

vuln.today AI

7.5 HIGH

Predictable DRBG lets an unauthenticated remote attacker recover secrets with low complexity, so AV:N/AC:L/PR:N/UI:N and C:H; integrity/availability rated N per vendor's confidentiality-only impact.

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

4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (Silabs).

CVSS VectorVendor: Silabs

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Analysis Generated

Jul 23, 2026 - 21:32 vuln.today

CVE Published

Jul 23, 2026 - 21:05 cve.org

HIGH 8.7

DescriptionCVE.org

A bug in the entropy initialization for SiWx917 causes the DRBG to use a predictable seed. As such, all random numbers generated in the Matter code use the same stream of numbers. This vulnerability was discovered after the impacted repository was already deprecated.

AnalysisAI

Predictable cryptographic randomness in Silicon Labs' Matter implementation for the SiWx917 wireless SoC allows attackers to reconstruct DRBG output because an entropy-initialization bug seeds the deterministic random bit generator with a predictable value, so every device produces the same stream of 'random' numbers. Any keys, nonces, or session material derived from this generator in the affected Matter code are therefore guessable, undermining confidentiality of secured communications on affected devices. The issue was found only after the repository was deprecated; no public exploit identified at time of analysis and it is not in CISA KEV.

Technical ContextAI

The affected component is Silicon Labs' Matter SDK/reference code running on the SiWx917 (a Wi-Fi/Bluetooth SoC targeting Matter smart-home devices). Matter relies on a properly seeded Deterministic Random Bit Generator (DRBG) to produce keys, nonces, and challenge values for its cryptographic operations. CWE-336 (Same Seed in Pseudo-Random Number Generator) is the root-cause class: because entropy initialization is broken, the DRBG is fed a fixed/predictable seed, collapsing the output space so all instances emit an identical, reproducible sequence. A DRBG is deterministic by design - its security rests entirely on unpredictable seed entropy - so a predictable seed reduces cryptographic strength toward zero regardless of algorithm quality.

RemediationAI

Update to the fixed Silicon Labs Matter code at the release_2.3.1-1.3 branch (https://github.com/SiliconLabs/matter/tree/release_2.3.1-1.3) - patch available per vendor advisory - and rebuild/reflash affected SiWx917 devices; consult the Silicon Labs advisory (https://siliconlabs.lightning.force.com/sfc/servlet.shepherd/document/download/a45Vm0000009SzZIAU) for migration guidance since the original repository is deprecated. Because the flaw poisons all previously generated key material, patching alone is insufficient: rotate/regenerate any cryptographic keys, certificates, and session credentials that were produced by the vulnerable DRBG, and re-commission affected Matter devices so new secrets are derived from properly seeded entropy. If immediate reflashing is not possible, compensating controls include isolating affected devices on a segmented network to reduce an attacker's ability to observe or reach Matter traffic, and treating any secrets from these devices as compromised - the trade-off is operational overhead and that segmentation does not restore cryptographic strength, only limits exposure.