# CVE-2026-47191: kas checks out SHA-like git branches as valid commits

> Attackers can trick kas into checking out malicious branches instead of validated commits, enabling supply chain attacks on Bitbake projects.

- **Severity:** Low 2.1 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:L/VI:L/VA:L/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:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 14 Aug 2026
- **Updated:** 18 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-47191, GHSA-qjwp-hrq6-r26r, PYSEC-2026-2544, UBUNTU-CVE-2026-47191

## What is CVE-2026-47191?

CVE-2026-47191 is a low-severity vulnerability in siemens kas, published on 14 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

kas is a setup tool for bitbake based projects. Prior to version 5.3, when relying solely on a git commit ID (SHA-1 or SHA-256) to qualify if a checkout of a repository is equivalent to the state validated while adding its commit ID to a kas configuration, users may be tricked to check out a branch of the same name from this repository. This implies that the referenced repository has been taken over by an attacker and modified to carry such a branch. SHA-1 commits may also be replaced by creating hash collisions, so the primary impact of this issue is on SHA-256 commit IDs. Version 5.3 fixes the issue. As a workaround, avoid relying solely on the commit ID for integrity validation of a repository that might become under control of a malicious 3rd party. If available, additional validate cryptographically signed commits or tags. Alternatively, mirror the repository to a save place, validate its integrity, and use this instead of the original one.

Weakness: CWE-347 (Improper Verification of Cryptographic Signature)

## Which versions are affected by CVE-2026-47191?

3 open source packages ship an affected version, including kas.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `kas` | PyPI | All versions | 5.3 |
| `kas` | PyPI | All versions | 5.3 |
| `kas` | PyPI | All versions | 5.3 |

## How do I fix CVE-2026-47191?

Upgrade kas to 5.3 or later.

## Is CVE-2026-47191 being exploited?

There is no known exploitation of CVE-2026-47191 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-47191 and fix it if it is affected.

What it is: CVE-2026-47191 is a low-severity vulnerability in siemens kas, published on 14 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-47191 in the wild and no public exploit code.

Affected packages and fixed versions:
- kas (PyPI): affected all versions; fixed in 5.3
- kas (PyPI): affected all versions; fixed in 5.3
- kas (PyPI): affected all versions; fixed in 5.3

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-2026-47191/ (Markdown: https://insights.sbomify.com/CVE-2026-47191/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-47191
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-47191
- OSV: https://osv.dev/vulnerability/CVE-2026-47191

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-47191/
Summaries are generated and may contain mistakes; the official description above is the record.