How severe is CVE-2018-18203?

CVE-2018-18203 has a CVSS 3.x base score of 6.4, rated medium severity. It is exploitable over physical access with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-18203 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-18203?

CVE-2018-18203 primarily affects Subaru Starlink 2017 Firmware. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-18203?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2018-18203 published?

CVE-2018-18203 was published on 2018-11-28 and last updated on 2026-06-17.

CVE-2018-18203

CVE-2018-18203 is a medium-severity vulnerability in Subaru Starlink 2017 Firmware with a CVSS 3.x base score of 6.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-347.

Key facts

Severity: Medium (CVSS 3.x base score 6.4)
CVSS v2: 6.9
EPSS exploit prediction: 0% (15th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-347
Affected product: Subaru Starlink 2017 Firmware
Published: 2018-11-28
Last modified: 2026-06-17

Description

A vulnerability in the update mechanism of Subaru StarLink Harman head units 2017, 2018, and 2019 may give an attacker (with physical access to the vehicle's USB ports) the ability to rewrite the firmware of the head unit. This occurs because the device accepts modified QNX6 filesystem images (as long as the attacker obtains access to certain Harman decryption/encryption code) as a consequence of a bug where unsigned images pass a validity check. An attacker could potentially install persistent malicious head unit firmware and execute arbitrary code as the root user.

Frequently asked questions

What is CVE-2018-18203?: A vulnerability in the update mechanism of Subaru StarLink Harman head units 2017, 2018, and 2019 may give an attacker (with physical access to the vehicle's USB ports) the ability to rewrite the firmware of the head unit. This occurs because the device accepts modified QNX6 filesystem images (as long as the attacker obtains access to certain Harman decryption/encryption code) as a consequence of a bug where unsigned images pass a validity check. An attacker could potentially install persistent malicious head unit firmware and execute arbitrary code as the root user.
How severe is CVE-2018-18203?: CVE-2018-18203 has a CVSS 3.x base score of 6.4, rated medium severity. It is exploitable over physical access with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-18203 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-18203?: CVE-2018-18203 primarily affects Subaru Starlink 2017 Firmware. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-18203?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-18203 published?: CVE-2018-18203 was published on 2018-11-28 and last updated on 2026-06-17.

References

https://github.com/sgayou/subaru_starlink_research

Affected products (3)

cpe:2.3:o:subaru:starlink_2017_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:subaru:starlink_2018_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:subaru:starlink_2019_firmware:-:*:*:*:*:*:*:*

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