CVE-2026-47191: Kas Kas Checks Out SHA-like Git Vulnerability

LOW
Advisory Identifier: GHSA-qjwp-hrq6-r26r
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CWE-347
Published
Advisory Summary

CVE-2026-47191 is a LOW kas checks out sha-like git vulnerability (CWE-347: Improper Verification of Cryptographic Signature) affecting Kas libraries in the PyPI ecosystem. The issue involves kas checks out sha-like git branches as valid commits. Remediation is available by upgrading affected packages to version 5.3.

CVE-2026-47191 at a Glance

CVE Identifier CVE-2026-47191
GHSA Identifier GHSA-qjwp-hrq6-r26r
Severity LOW
CVSS v3.1 Base Score N/A
CWE Classification CWE-347: Improper Verification of Cryptographic Signature
Affected Product Kas
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix CVE-2026-47191

To remediate this vulnerability, upgrade all affected Kas dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

kas fixed: 5.3 
pip install kas>=5.3
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show kas

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-47191, inspect your installed packages using pip:

pip show kas

Analyze the terminal output to locate any version of Kas in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 5.3), your application is affected.

Note: The pip show kas command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-347: Improper Verification of Cryptographic Signature, where the product does not verify, or incorrectly verifies, the cryptographic signature for data. In Kas, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact 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. ### Patches Commit https://github.com/siemens/kas/commit/4cb4a3d01122ffaec9feaae768a5814092f6f9b5 is resolving this issue. It has been released along with kas version 5.3. ### Workarounds 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. ### Credits That such issues exist was already reported 3 years ago by Aditya Sirish A Yelgundhalli. At this point, no strong integrity checks for external repositories were in place in kas, and Siemens stated in the kas documentation that such attacks are considered out of scope. This hasn't changed for SHA-1 commits as explained above. If a repo provides SHA-256 commits, though, those may be considered strong enough (even if not providing authenticity proof) and can be affected by this issue.

CVE-2026-47191 Affected Kas Versions

1 component(s)
Fixed Versions:
5.3
Product / Package Ecosystem Affected Versions Fixed Version
kas
pypi/kas
PyPI
< 5.3
5.3

References

GitHub Advisory / Wiki ADVISORY
https://github.com/siemens/kas/security/advisories/GHSA-qjwp-hrq6-r26r
Security Fix Commit FIX COMMIT
https://github.com/siemens/kas/commit/4cb4a3d01122ffaec9feaae768a5814092f6f9b5
Kas Source Repository REPOSITORY
https://github.com/siemens/kas

Frequently Asked Questions

What is CVE-2026-47191?
CVE-2026-47191 is a security vulnerability in Kas involving kas checks out SHA-like git branches as valid commits under CWE-347: Improper Verification of Cryptographic Signature.
Which Kas versions are affected?
Affected versions include releases prior to 5.3 across affected packages: kas.
What version fixes CVE-2026-47191?
Upgrading to 5.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is kas affected?
Yes, kas is affected in releases prior to 5.3. Upgrade your dependency to 5.3 or later.
What CWE is associated with CVE-2026-47191?
CVE-2026-47191 is classified under CWE-347: Improper Verification of Cryptographic Signature (The product does not verify, or incorrectly verifies, the cryptographic signature for data.).
How can I check PyPI dependencies for CVE-2026-47191?
Run the dependency tree command: 'pip show kas'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-qjwp-hrq6-r26r",
  "modified" : "2026-06-01T14:26:36Z",
  "published" : "2026-06-01T14:26:36Z",
  "aliases" : [ "CVE-2026-47191" ],
  "summary" : "kas checks out SHA-like git branches as valid commits",
  "details" : "### Impact\nWhen 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.\n\n### Patches\nCommit https://github.com/siemens/kas/commit/4cb4a3d01122ffaec9feaae768a5814092f6f9b5 is resolving this issue. It has been released along with kas version 5.3.\n\n### Workarounds\nAvoid 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.\n\n### Credits\nThat such issues exist was already reported 3 years ago by Aditya Sirish A Yelgundhalli. At this point, no strong integrity checks for external repositories were in place in kas, and Siemens stated in the kas documentation that such attacks are considered out of scope. This hasn't changed for SHA-1 commits as explained above. If a repo provides SHA-256 commits, though, those may be considered strong enough (even if not providing authenticity proof) and can be affected by this issue.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "kas"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/siemens/kas/security/advisories/GHSA-qjwp-hrq6-r26r"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/siemens/kas/commit/4cb4a3d01122ffaec9feaae768a5814092f6f9b5"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/siemens/kas"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-347" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-01T14:26:36Z",
    "nvd_published_at" : null
  }
}