# CVE-2026-62943: btrbk: SSH Command Filter Bypass in ssh_filter_btrbk.sh

> Attackers with restricted SSH access can bypass command filters in btrbk to execute arbitrary commands on the backup target system.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 18 Sep 2026
- **Updated:** 21 Sep 2026
- **Also known as:** DEBIAN-CVE-2026-62943, GHSA-pf45-7g54-65h5, UBUNTU-CVE-2026-62943

## What is CVE-2026-62943?

CVE-2026-62943 is a high-severity command injection vulnerability in digint btrbk, published on 18 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

btrbk is a tool for creating snapshots and remote backups of Btrfs subvolumes. From 0.29.0 until 0.32.7, btrbk's ssh_filter_btrbk.sh constructs allow_stream_match with a start anchor but without an end-of-string anchor for the complete command. A user restricted through an authorized_keys forced command can append a trailing pipe command after a valid btrbk command prefix, bypassing the allowlist and executing arbitrary commands with the privileges of the backup-target SSH account. Deployments that do not use ssh_filter_btrbk.sh in authorized_keys are not affected. This issue is fixed in version 0.32.7.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2026-62943?


## How do I fix CVE-2026-62943?

No fix has been published for CVE-2026-62943 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-62943 being exploited?

There is no known exploitation of CVE-2026-62943 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-62943 and fix it if it is affected.

What it is: CVE-2026-62943 is a high-severity command injection vulnerability in digint btrbk, published on 18 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-62943 in the wild and no public exploit code.

Affected product: digint btrbk. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-62943/ (Markdown: https://insights.sbomify.com/CVE-2026-62943/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-62943
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-62943
- OSV: https://osv.dev/vulnerability/CVE-2026-62943

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-62943/
Summaries are generated and may contain mistakes; the official description above is the record.