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Vulnerabilities

Vulnerability · CVE-2021-4459

An authorized remote attacker can access files and directories outside the intended web root, potentially exposing sensitive system information of the affected Sunny Boy devices.

Published Aug 27, 2025 · catalog updated Aug 27, 2025 · SMA Boy 4.0

Last checked Oct 29, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2021-4459. EPSS is 0.67%. Act only if a listed version of SMA Boy 4.0 is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.67%
Remediation
Version ranges on file
Affected products
vendor SMA Boy 4.0 0.0.0 <3.10.27.R

An authorized remote attacker can access files and directories outside the intended web root, potentially exposing sensitive system information of the affected Sunny Boy devices.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor SMA Boy 4.0 0.0.0 <3.10.27.R0.0.0 <3.10.27.R

How to fix CVE-2021-4459

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2021-4459. EPSS is 0.67%. Act only if a listed version of SMA Boy 4.0 is installed.

Which versions are affected?

Compare what you have installed with SMA Boy 4.0 0.0.0 <3.10.27.R 0.0.0 <3.10.27.R. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.67%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 27, 2025 · EUVD

    Detected

    An authorized remote attacker can access files and directories outside the intended web root, potentially exposing sensitive system information of the affected Sunny Boy devices.

  2. Aug 27, 2025 · EUVD

    Updated

    An authorized remote attacker can access files and directories outside the intended web root, potentially exposing sensitive system information of the affected Sunny Boy devices.

Sources

  • CVE.orgVulnerability recordCVE-2021-4459

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-4459

    30-day exploitation probability 0.67%

    first.org
  • EUVDVulnerability recordEUVD-2021-34684

    An authorized remote attacker can access files and directories outside the intended web root, potentially exposing sensitive system information of the affected Sunny Boy devices.

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 29, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 23, 2026
  • CVE.orgOct 22, 2026
  • EUVDOct 22, 2026