CVE-2026-44937
Received Received - Intake

Unauthenticated Webhook Forgery in SUSE Rancher Fleet

Publication date: 2026-07-06

Last updated on: 2026-07-06

Assigner: SUSE

Description
Potential forgery of webhook requests when using a unauthenticated webhook in SUSE Rancher Fleet 0.15 before 0.15.2, 0.14 before 0.14.6, 0.13 before 0.13.11 and 0.12 before 0.12.5 could be used by remote attackers to cause a denial of service or a downgrade attack on other repositories on the system.

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Meta Information

Published
2026-07-06
Last Modified
2026-07-06
Generated
2026-07-06
AI Q&A
2026-07-06
EPSS Evaluated
N/A
NVD
CVE-2026-44937
EUVD
EUVD-2026-41867

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
suse rancher_fleet From 0.12.0 (inc) to 0.15.1 (inc)
suse rancher_fleet to 0.13.11 (exc)
suse rancher_fleet to 0.14.6 (exc)
suse rancher_fleet to 0.15.2 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-918 The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

Attack-Flow Graph

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Executive Summary

CVE-2026-44937 is a high-severity vulnerability in Rancher Fleet versions 0.12.0 up to 0.15.1 involving an unauthenticated webhook endpoint.

The vulnerability arises because the webhook endpoint does not sanitize repository URL components, making it vulnerable to regex injection.

When webhooks are configured without a secret, attackers can forge requests without needing to know the specific repository or path.

Impact Analysis

Exploitation of this vulnerability can cause continuous repository re-cloning, which increases network traffic and depletes resources on the management cluster.

Attackers can also perform downgrade attacks by forcing running services to revert to any historical revision in the Git repository.

This can lead to denial of service conditions and potentially disrupt service availability.

Detection Guidance

This vulnerability involves unauthenticated webhook requests being forged, which can cause continuous repository re-cloning and increased network traffic. Detection can focus on monitoring unusual webhook activity or excessive repository cloning events.

  • Monitor network traffic for repeated webhook requests to the Rancher Fleet webhook endpoint.
  • Check logs for repeated or suspicious webhook calls without authentication.
  • Use commands like 'curl' or 'wget' to simulate webhook requests and observe system responses.
  • Example command to check webhook endpoint response: curl -v http://<fleet-server>/v1-webhook/git/<repository-path>
  • Use system monitoring tools to detect spikes in resource usage or network traffic related to repository cloning.
Mitigation Strategies

To mitigate this vulnerability immediately, upgrade Rancher Fleet to a patched version that sanitizes repository URLs.

  • Upgrade to one of the following versions: 0.12.15, 0.13.11, 0.14.6, or 0.15.2.
  • If upgrading is not possible immediately, enable webhooks with a shared secret to prevent unauthenticated requests.

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