CVE-2026-67349: opencost advisory

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

What it is

OpenCost before 1.121.0 fails to authenticate the GET /helmValues endpoint, exposing base64-decoded HELM_VALUES environment variable containing cloud provider credentials. Additionally, adminAuthMiddleware fails open when ADMIN_TOKEN is unset, allowing unauthenticated attackers to modify GCP service account keys via POST /serviceKey to redirect billing calls.

Description quoted from the CVE record (assigned by VulnCheck, published 2026-07-30).

Weakness: Missing Authentication for Critical Function

How it can be exploited

Exploitable over the network with low attack complexity with no special attack requirements needing no privileges and no user interaction. Impact: confidentiality high, integrity none, availability none. CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

CISA assessment (SSVC): CISA assesses that a public proof of concept exists. Automatable: yes. Technical impact: partial.

Public exploit evidence (Exploit Observer)

Exploit Observer found 5 code repositories naming this CVE.

Code repositories that name a CVE are often scanners, copies or fakes, and some are malware. Read the code before running anything.

See all 8 references on Exploit Observer

Live scores

EPSS: 0.005
low predicted chance of attack
VEDAS: 0.985
strong exploit evidence
On CISA KEV: Not listed
Detection rule: Nuclei · Suricata

Who is affected

Product	Affected	Not affected
opencost	before 1.121.0	Not stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

How to fix it

Fixed versions stated in the CVE record: 1.121.0.

Vendor guidance:

OpenCost core/v1.121.0 Release Notes (release-notes)
Pull Request (issue-tracking, patch)
Patch Commit (patch)

How to detect it

Nuclei template (active check)

OpenCost - Missing Authentication on /helmValues Endpoint
OpenCost before 1.121.0 fails to authenticate the GET /helmValues endpoint, exposing the base64-decoded HELM_VALUES environment variable which can contain cloud provider credentials. The handler sets a permissive CORS policy and returns the decoded values (or “Values reporting disabled” when unset) to any network-reachable client with no credentials. This template issues an unauthenticated GET /helmValues request and confirms the handler executed without an auth gate.

Name and description quoted from the template, written by VEDAS.

The template sends 1 request (GET /helmValues); it decides using regex, status, word matchers. Severity in the template: high. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

bash

nuclei -u https://your-host -t CVE-2026-67349.yaml

Show the template (44 lines)

yaml

id: CVE-2026-67349

info:
  name: "OpenCost - Missing Authentication on /helmValues Endpoint"
  author: vedas-arpsyndicate
  severity: high
  description: |
    OpenCost before 1.121.0 fails to authenticate the GET /helmValues endpoint, exposing the
    base64-decoded HELM_VALUES environment variable which can contain cloud provider credentials.
    The handler sets a permissive CORS policy and returns the decoded values (or "Values reporting
    disabled" when unset) to any network-reachable client with no credentials. This template issues
    an unauthenticated GET /helmValues request and confirms the handler executed without an auth gate.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2026-67349&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=opencost&match=exact
  classification:
    cvss-metrics: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
    cvss-score: 8.7
    cve-id: CVE-2026-67349
    cwe-id: CWE-306
  metadata:
    verified: false
  tags: cve,cve2026,opencost,exposure,auth-bypass

http:
  - raw:
      - |
        GET /helmValues HTTP/1.1
        Host: {{Hostname}}
        Accept: */*

    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        part: header
        words:
          - "Access-Control-Allow-Origin: *"
      - type: regex
        part: body
        regex:
          - '(?i)(values reporting disabled|kubecost|networkCosts|clusterController|prometheus|grafana|^global:)'

CVE-2026-67349.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2026-67349 OpenCost - Unauthenticated Access to /helmValues. Add them to your Suricata rule set and reload.

Show the rules

suricata

alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2026-67349 OpenCost - Unauthenticated Access to /helmValues"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/helmValues"; fast_pattern; classtype:web-application-attack; reference:cve,CVE-2026-67349; reference:url,https://www.exploit.observer/?keyword=CVE-2026-67349&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=opencost&match=exact; sid:1081801; rev:1;)

CVE-2026-67349.rules on GitHub

References

Vendor advisories and patches

OpenCost core/v1.121.0 Release Notes (release-notes)
Pull Request (issue-tracking, patch)
Patch Commit (patch)

Exploit code

Researcher Disclosure (technical-description, exploit, issue-tracking)

Technical analysis and advisories

https://www.vulncheck.com/advisories/opencost-unauthenticated-helm-values-exposure-and-admin-bypass (third-party-advisory)

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.