CVE-2021-43327Known exploitationPublic exploit

Firmware disclosure via timed VCC glitch

Published Dec 2, 2021 · Updated Aug 4, 2024

Fault injection in Renesas RX65 and RX65N devices allows physically proximate attackers to extract protected firmware through VCC glitching. A timed power glitch at the VCL core-supply pin after the FINE Serial Programming ID Code Check causes protected option-setting memory, including the 16-byte security ID, to be returned. Physical access, removal of the VCL stabilization capacitor, FINE-interface control, and precise timing are required; disclosure is limited to device secrets and firmware.

CVSS severity4.6
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Fault injection in Renesas RX65 and RX65N devices allows physically proximate attackers to extract protected firmware through VCC glitching. A timed power glitch at the VCL core-supply pin after the FINE Serial Programming ID Code Check causes protected option-setting memory, including the 16-byte security ID, to be returned. Physical access, removal of the VCL stabilization capacitor, FINE-interface control, and precise timing are required; disclosure is limited to device secrets and firmware.

The record

CVE
CVE-2021-43327
Published
Dec 2, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
Unavailable
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 2, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.6NIST NVDCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
2.1NIST NVDAV:L/AC:L/Au:N/C:P/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo