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Public proof of conceptFix available

CVE-2020-8289

A public proof of concept exists; no exploitation attested.

  • Published2020-12-27
  • Fixed in7.0.1.434 · 7.0.1.433
  • WeaknessCWE-295

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2020-12-2702:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-8289?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-8289?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Backblaze
BranchAffectedFixed in
7.0< 7.0.1.4347.0.1.434
7.0< 7.0.1.4337.0.1.433

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Backblaze to 7.0.1.434 · 7.0.1.433

Detection

read 2026-11-03 22:42 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
1 repository, unverifiedgeffner/CVE-2020-8289
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.17.8read 2026-10-23
  • NVDCVSS 2.09.3read 2026-10-23
  • CNAweakness (CWE)CWE-295known since 2026-10-23
  • NVDweakness (CWE)CWE-295read 2026-10-23
  • FIRST EPSSEPSS score4.7 %2026-11-03
  • PoC-in-GitHubproof of concept1read 2026-11-03

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Published
2020-12-27
Last Modified
2026-06-17
NVD status
Modified

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.

Is CVE-2020-8289 actively exploited?

Active exploitation of CVE-2020-8289 has not been confirmed. Its EPSS score was 4.7% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-8289?

CVE-2020-8289 has a CVSS v3 base score of 7.8 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

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Sources for this record