CVE-2023-28904Public exploit

Persistent code execution via mismatched image sizes

Published Jun 28, 2025 · Updated Jun 30, 2025

Buffer overflow in the bootloader of JOYNEXT MIB3 OI MQB through 0304 allows physically proximate attackers to bypass secure boot. The bl2.bin bootloader trusts an unsigned PCCP decompressed-size field but verifies only the certificate-declared size, allowing appended LZ4 data to overwrite RAM or extend a signed initrd. Exploitation requires physical access and prior root-level code execution to rewrite SPI boot images, after which arbitrary code persists across reboot.

CVSS severity5.2
Medium
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in the bootloader of JOYNEXT MIB3 OI MQB through 0304 allows physically proximate attackers to bypass secure boot. The bl2.bin bootloader trusts an unsigned PCCP decompressed-size field but verifies only the certificate-declared size, allowing appended LZ4 data to overwrite RAM or extend a signed initrd. Exploitation requires physical access and prior root-level code execution to rewrite SPI boot images, after which arbitrary code persists across reboot.

The record

CVE
CVE-2023-28904
Published
Jun 28, 2025
Updated
Jun 30, 2025
Vendor
JOYNEXT GmbH
Product
JOYNEXT MIB3 OI MQB
Classifications
CWE-120, CAPEC-100, T1542.001
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 28, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 30, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=0304

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

JOYNEXT GmbH · JOYNEXT MIB3 OI MQBversion=0 <=0304

Published CVSS scores

5.2Automotive Security Research Group (ASRG)CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CAPEC-100Overflow Buffers
T1542.001Pre-OS Boot: System Firmware

Public exploit references

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

Technologies

Your stack

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Your stack

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