SSRF (Server-Side Request Forgery) in github.com/rancher/fleet (CVE-2026-44936)
Summary
SSRF in github.com/rancher/fleet (CVE-2026-44936). Risk of unauthorized operations or information disclosure. Exploitable via helmRepoURLRegex. Mitigation: upgrade to 0.12.15 or later.
Original description
The description as published by the source.
Impact
A vulnerability has been identified in Fleet when the helmRepoURLRegex field isn't set on a GitRepo resource. Fleet's bundle reader forwards Helm authentication credentials (BasicAuth) to any URL specified in the helm.repo field of a fleet.yaml file.
An attacker with git push access to a Fleet-monitored repository can exploit this behavior by specifying a malicious URL in helm.repo. This causes the Fleet controller to send the configured Helm repository credentials to the attacker’s server.
As a result, the attacker can capture the username and password that an administrator configured to access a private Helm chart repository. However, the response body from the attacker's server isn't included in the error message (this behavior was fixed in Fleet v0.13.3 and later), which prevents additional internal data from leaking through the status condition.
The final severity of this vulnerability depends on the specific permissions of the leaked credentials.
Fleet recommends you to:
- Review your system for potentially leaked credentials.
- Replace any credentials that might be compromised.
Please consult the associated MITRE ATT&CK - Technique - Stored Data Manipulation and MITRE ATT&CK - Technique - Steal Application Access Token for further information about this category of attack.
Patches
To resolve this vulnerability, upgrade to a patched vers…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-44936 has been found in github.com/rancher/fleet.
Attackers can target a specific entry point like helmRepoURLRegex over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.0/10.
What to do: upgrade github.com/rancher/fleet to 0.12.15 or later.
If unsure, ask your IT team or search "github.com/rancher/fleet CVE-2026-44936" on the vendor's site.
CVE-2026-44936 (github.com/rancher/fleet) — CWE-918 / CVSS v3 5.0
Attack vector: remote (network-reachable) / no user interaction
Attack surface: helmRepoURLRegex / GitRepo / BasicAuth / helm.repo
Patched: 0.12.15 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
SSRF (CWE-918) exists in github.com/rancher/fleet. Attackers reach the vulnerable code path via helmRepoURLRegex.
Check the vendor advisory for the affected versions of github.com/rancher/fleet. Attack surface: helmRepoURLRegex / GitRepo / BasicAuth / helm.repo.
Severity: Medium (CVSS 5.0/10). Risk of unauthorized operations or information disclosure.
Update to 0.12.15.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/rancher/fleet' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'github.com/rancher/fleet' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
github.com/rancher/fleetを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade github.com/rancher/fleet to 0.12.15ステージング環境で 0.12.15 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- exploit meissner@suse.de
- package github.com
- web github.com