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Esp32 D0wd V3 FirmwareOperating system · Espressif

CVE-2023-35818

MEDIUM · 6.8 CVSS v3.1 Published 2023-07-17
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
73/100
Remediation priority · Elevated
No privileges Zero-click

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 on Espressif ESP32 3.0 (ESP32_rev300 ROM) devices. An EMFI attack on ECO3 provides the attacker with a capability to influence the PC value at the CPU context level, regardless of Secure Boot and Flash Encryption status. By using this capability, the attacker can exploit another behavior in the chip to gain unauthorized access to the ROM download mode. Access to ROM download mode may be further exploited to read the encrypted flash content in cleartext format or execute stub code.

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 · high confidence

EMFI (Electromagnetic Fault Injection) attack on ESP32 ECO3 silicon revision allows attackers to manipulate the Program Counter (PC) register at the CPU context level, bypassing both Secure Boot and Flash Encryption. This PC manipulation enables unauthorized access to ROM download mode, which can then be exploited to read encrypted flash contents in plaintext or execute arbitrary stub code.

MitigationNo software patch can remediate this hardware-level vulnerability; ECO3 silicon must be replaced with a fixed revision. Consider physical security controls to limit EMFI attack exposure until hardware is upgraded.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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
Esp32 D0wd V3 FirmwareOperating system
Affected:= 3.0= 3.1
Esp32 D0wdr2 V3 FirmwareOperating system
Affected:= 3.0= 3.1
Esp32 U4wdh FirmwareOperating system
Affected:= 3.0= 3.1
Esp32 Pico V3 FirmwareOperating system
Affected:= 3.0= 3.1
Esp32 Pico V3 02 FirmwareOperating system
Affected:= 3.0= 3.1
Esp32 Pico D4 FirmwareOperating system
Affected:= 3.0= 3.1
Esp32 Wroom 32e FirmwareOperating system
Affected:= 3.0= 3.1
Esp32 Wroom 32ue FirmwareOperating system
Affected:= 3.0= 3.1

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
Physical
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the ESP32 silicon revision
    Use esptool.py with the command 'python esptool.py -p /dev/ttyUSB0 chip_id' or read the chip's eFuse to determine the silicon revision (look for ECO3 or revision 3)
    Affected if The silicon revision is ECO3 (revision 3) on any of the affected chip variants
  2. Identify the exact ESP32 chip model
    Run 'python esptool.py -p /dev/ttyUSB0 chip_id' or check the markings on the physical chip package
    Affected if The chip is one of: ESP32-D0WD V3, ESP32-D0WD-R2 V3, ESP32-U4WDH, ESP32-PICO-V3, ESP32-PICO-V3-02, ESP32-PICO-D4, ESP32-WROOM-32E, or ESP32-WROOM-32UE
  3. Identify the firmware version
    Check the firmware version via esptool.py 'python esptool.py -p /dev/ttyUSB0 read_flash 0x1000 16' or consult your build documentation/partition table
    Affected if The firmware version is exactly 3.0 or 3.1 on any of the affected chip models
  4. Verify if Secure Boot or Flash Encryption is enabled
    Check eFuse configuration using 'python esptool.py -p /dev/tTYUSB0 efuse_summary' to see if ABS_DONE_0 (Secure Boot) or FLASH_CRYPT_CNT (Flash Encryption) are set
    Affected if Secure Boot or Flash Encryption are enabled AND the chip is an affected ECO3 variant with firmware 3.0/3.1 - the device is exposed because the attack bypasses these protections

You are affected if your ESP32 uses ECO3 silicon revision with any of the listed firmware versions (3.0 or 3.1), regardless of whether Secure Boot or Flash Encryption is enabled, as these protections are bypassed by this hardware vulnerability.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

No software patch can remediate this hardware-level vulnerability; ECO3 silicon must be replaced with a fixed revision. Consider physical security controls to limit EMFI attack exposure until hardware is upgraded.

Recommended fix Moderate confidence

ESP32 Firmware 3.2 or later (or latest stable release)

  1. Identify the specific ESP32 variant in use from the affected products list (D0wd V3, D0wdr2 V3, U4wdh, Pico V3, Pico V3 02, Pico D4, Wroom 32e, or Wroom 32ue)
  2. Download the latest ESP32 firmware version (3.2 or later) from the official Espressif website at espressif.com
  3. Verify firmware integrity using Espressif's published checksums
  4. Update the ESP32 module firmware using ESP-IDF tools (esptool.py) or Espressif's flashing tools
  5. After update, verify the ROM version has been updated to a version beyond rev300
  6. If physical security is critical, consider whether the hardware revision (silicon step) also needs to be upgraded to a newer silicon revision if available
Caveat Review Espressif release notes for any API changes between 3.0/3.1 and the target version, as application code adjustments may be required

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

Fix this in Esp32 D0wd V3 Firmware Scoped from the published advisory
  • Consultation8.0 h
  • Testing4.0 h
  • Review / QA4.0 h
16.0 hours of engineering $2,920
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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-2023-35818 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data