How severe is CVE-2020-8289?

CVE-2020-8289 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-8289 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-8289?

CVE-2020-8289 primarily affects Backblaze. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-8289?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2020-8289 published?

CVE-2020-8289 was published on 2020-12-27 and last updated on 2026-06-17.

CVE-2020-8289

CVE-2020-8289 is a high-severity vulnerability in Backblaze with a CVSS 3.x base score of 7.8. 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-295.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 9.3
EPSS exploit prediction: 5% (91st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-295
Affected product: Backblaze
Published: 2020-12-27
Last modified: 2026-06-17

Description

Backblaze for Windows before 7.0.1.433 and Backblaze for macOS before 7.0.1.434 suffer from improper certificate validation in `bztransmit` helper due to hardcoded whitelist of strings in URLs where validation is disabled leading to possible remote code execution via client update functionality.

Frequently asked questions

What is CVE-2020-8289?: Backblaze for Windows before 7.0.1.433 and Backblaze for macOS before 7.0.1.434 suffer from improper certificate validation in `bztransmit` helper due to hardcoded whitelist of strings in URLs where validation is disabled leading to possible remote code execution via client update functionality.
How severe is CVE-2020-8289?: CVE-2020-8289 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-8289 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-8289?: CVE-2020-8289 primarily affects Backblaze. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-8289?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-8289 published?: CVE-2020-8289 was published on 2020-12-27 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:backblaze:backblaze:*:*:*:*:*:windows:*:*
cpe:2.3:a:backblaze:backblaze:*:*:*:*:*:macos:*:*

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