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CVE-2025-3873· NVD / CVE Program· CNA Silabs

Buffer overflow in Si91x crypto APIs

The following APIs for the Silcon Labs SiWx91x prior to vesion 3.4.0 failed to check the size of the output buffer of the caller which could lead to data corruption on the host (Cortex-M4) application. sl_si91x_aes sl_si91x_gcm sl_si91x_ccm sl_si91x_sha

MediumCVSS 6.0 · v4.0—No exploit Fix available
Published
Jul 25, 2025
Updated
Jun 17, 2026
EPSS
0.3% · 21th percentile
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Action score

24

Monitor

Low priority for now.

CVSS
24 / 40 · 6.0 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Silabs
6.0
NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Silabs). Independent of NVD's CPE analysis and usually ahead of it.

  • silabs.com WiseConnect

    • 3.0.0 and later · before 3.4.0affected · semver

Same product

silabs.com: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-19293SMP security request
    35Monitor
  • CVE-2026-19292Bluetooth re-pairing with legitimate device can use lower security level
    35Monitor
  • CVE-2026-19291Bluetooth re-pairing can use a lower security level than previous
    35Monitor
  • CVE-2026-16101forced re-pairing with already bonded device
    35Monitor
  • CVE-2026-65935Bypassing passkey entry in legacy pairing
    30Monitor
  • CVE-2026-65936RS9116W/SiWx917 malformed packet with increased length field causes memory leak
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
silabs.com WiseConnect3.4.0Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
X

Weakness class (CWE)

CWE-787 · Out-of-bounds Write

CVSS vector

CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:L/VI:H/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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

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Change log

  1. Fix✗ → ✓

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References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records