Authorization Flaw in github.com/portainer/portainer (CVE-2026-44882)
Summary
Vulnerability in github.com/portainer/portainer (CVE-2026-44882). Confidential information can be exposed externally. Exploitable via kubeClientMiddleware. Mitigation: upgrade to 2.33.8 or later.
Original description
The description as published by the source.
Portainer Community Edition is a lightweight service delivery platform for containerized applications that can be used to manage Docker, Swarm, Kubernetes and ACI environments. From 2.33.0 to before 2.33., Portainer proxies requests to Kubernetes clusters through a middleware layer (kubeClientMiddleware) that validates the requesting user's token before forwarding traffic to the cluster. When security.RetrieveTokenData returned an error, the middleware wrote an HTTP 403 response but was missing a return statement — execution continued into the handler with a nil tokenData value. The Kubernetes endpoints sit behind Portainer's outer AuthenticatedAccess bouncer, so an attacker requires a valid Portainer session. However, a user whose secondary token validation fails in kubeClientMiddleware — for example a user without permission to access a given Kubernetes endpoint — would have their request forwarded to the cluster anyway, bypassing the authorization check. The same defect was present in both the CE and EE codebases. This vulnerability is fixed in 2.33.8.
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-2026-44882 has been found in github.com/portainer/portainer.
Attackers can target a specific entry point like kubeClientMiddleware over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 8.1/10.
What to do: upgrade github.com/portainer/portainer to 2.33.8 or later.
If unsure, ask your IT team or search "github.com/portainer/portainer CVE-2026-44882" on the vendor's site.
CVE-2026-44882 (github.com/portainer/portainer) — CWE-863 / CVSS v3 8.1
Attack vector: remote (network-reachable) / no user interaction
Attack surface: kubeClientMiddleware / security.RetrieveTokenData / return / tokenData
Patched: 2.33.8 — 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.
Incorrect authorization (CWE-863) exists in github.com/portainer/portainer. Attackers reach the vulnerable code path via kubeClientMiddleware.
Check the vendor advisory for the affected versions of github.com/portainer/portainer. Attack surface: kubeClientMiddleware / security.RetrieveTokenData / return / tokenData.
Severity: High (CVSS 8.1/10). Confidential information can be exposed externally.
Update to 2.33.8.
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/portainer/portainer' . 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/portainer/portainer' . | 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/portainer/portainer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/portainer/portainer to 2.33.8ステージング環境で 2.33.8 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
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- web github.com
- web github.com