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

> Unauthenticated attackers can execute arbitrary commands via SSH ProxyCommand injection when Kopia's HTTP server is configured with --insecure and --without-password.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Jul 2026
- **Updated:** 16 Jul 2026
- **Also known as:** GHSA-2q4c-3mrw-63c3, GO-2026-5009

## What is CVE-2026-45695?

CVE-2026-45695 is a critical command injection vulnerability in kopia, published on 16 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command), CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2026-45695?

3 open source packages ship an affected version, including github.com/kopia/kopia.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/kopia/kopia` | Go | All versions | 0.23.0 |
| `github.com/kopia/kopia` | Go | All versions | 0.23.0 |
| `github.com/kopia/kopia` | Go | All versions | 0.23.0 |

## How do I fix CVE-2026-45695?

Upgrade github.com/kopia/kopia to 0.23.0 or later.

## Is CVE-2026-45695 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-45695 exists.

Public exploit code:

- Kopia Server 0.23.0 - Remote Code Execution (nuclei): http/cves/2026/CVE-2026-45695.yaml

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-45695 and fix it if it is affected.

What it is: CVE-2026-45695 is a critical command injection vulnerability in kopia, published on 16 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-45695 exists.

Affected packages and fixed versions:
- github.com/kopia/kopia (Go): affected all versions; fixed in 0.23.0
- github.com/kopia/kopia (Go): affected all versions; fixed in 0.23.0
- github.com/kopia/kopia (Go): affected all versions; fixed in 0.23.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-45695/ (Markdown: https://insights.sbomify.com/CVE-2026-45695/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-45695
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-45695
- OSV: https://osv.dev/vulnerability/CVE-2026-45695

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-45695/
Summaries are generated and may contain mistakes; the official description above is the record.