CVE-2026-82855

Executive Summary

CVE-2026-82855 is a critical evidence validation bypass vulnerability affecting the @hulumi/policies package (versions before 1.3.2) and its associated Cloudflare and deployment-governance validators. An unauthenticated attacker can exploit this flaw to submit unrelated compliant evidence—drawing from different zones, hostnames, origins, or repositories—to suppress security violations for entirely different, unrelated resources within the same deployment stack. With a CVSS score of 9.8 and a full C:H/I:H/A:H impact rating, this vulnerability enables comprehensive security-guardrail circumvention without requiring authentication or user interaction. The vulnerability holds a CWE-693 designation (Protection Mechanism Failure), reflecting the core flaw: the validation logic fails to properly associate evidence with the resource it is meant to protect. No public PoC, exploit code, or CISA KEV inclusion has been reported at the time of writing; however, the high severity and network-exposed nature of affected validators should prompt immediate mitigation action.

Technical Analysis

The vulnerability resides in the @hulumi/policies npm package, specifically within its Cloudflare and deployment-governance validators. The NVD description identifies an "evidence validation bypass" mechanism: the validator logic fails to enforce a strict binding between submitted evidence and the target resource being validated. Instead of confirming that evidence pertains to the exact zone, hostname, origin, or repository under review, the validator accepts any syntactically valid compliant evidence and applies it toward suppression of violations.

The underlying failure maps directly to CWE-693 (Protection Mechanism Failure), which describes a scenario where a protection mechanism is implemented but either incomplete or incorrectly applied to a subset of assets. In this instance, the protection mechanism—the compliance/evidence validation gate—is present and functions nominally, but its scope of enforcement is incorrect. It validates that the evidence itself is compliant (e.g., properly formatted, from an approved source pattern) but fails to validate that the evidence is relevant to the specific resource being checked.

The attack surface is the network-facing API or interface of the deployment-governance validator. Attackers require no authentication (PR:N), and the flaw is remotely exploitable (AV:N) with no user interaction (UI:N). The attack complexity is low (AC:L), meaning there are no special conditions beyond HTTP(S) network access that must be met.

This is fundamentally an authorization or association failure within a policy enforcement point, not a memory-corruption or injection flaw. The attacker does not overwrite memory or inject malicious content; rather, they exploit a logical gap in how compliance evidence is correlated with stack resources. The package compares evidence against a set of compliance rules but does not maintain—or does not properly consult—a mapping of which evidence identifies which resource.

Technical detail is sparse in the publicly available description. No specific function names, class names, API endpoints, or file paths within the @hulumi/policies codebase are disclosed in the NVD description, and the tooling does not provide deeper code-level context. The vulnerability class is clear, however: evidence/policy association failure leading to control bypass.

Exploitation Scenarios

No public PoC or exploit code is currently available, and the NVD description lacks step-by-step technical detail. The attack chain below is inferred from the vulnerability class and the description's explicit statements about cross-zone, cross-hostname, cross-origin, and cross-repository evidence reuse.

Step 1 — Reconnaissance and Target Identification The attacker first identifies a target deployment stack that uses Cloudflare and deployment-governance validators from @hulumi/policies. This stack may be exposed through a management API, CI/CD pipeline validation endpoint, or governance dashboard. The attacker enumerates the target's declared zones, hostnames, origins, or repositories through public DNS, certificate transparency logs, public project metadata, or unauthenticated information-disclosure endpoints. No authentication is required to reach the vulnerable check.

Step 2 — Flaw Trigger The attacker identifies its own—or another unrelated—resource that possesses compliant evidence: a valid certificate, a passing security scan, a compliant repository configuration, or any other artifact the validator recognizes as satisfying the policy. The attacker then submits this evidence to the validation process for the target resource. Because the validator fails to bind evidence to its true originating resource, it accepts the unrelated evidence as proof of the target's compliance.

Step 3 — Exploitation Method (Vulnerability-Class Level) The exploitation technique is evidence substitution or cross-resource evidence recycling. The attacker crafts a validation request for the target zone/hostname/origin/repository but attaches compliant evidence harvested from a different resource. At the vulnerability-class level, this is a form of data-relevance validation bypass: the validator's parsing logic accepts the evidence's format but does not verify its ownership or scope correlation. The request itself appears legitimate; no malicious payload is needed because the attack exploits the validator's logical association gap rather than a memory or parsing flaw.

Step 4 — Post-Exploitation Impact Once the unrelated evidence is accepted and violations are suppressed, the attacker achieves three outcomes: (a) Integrity failure — the attacker's own non-compliant resources can be marked compliant, allowing insecure configurations (e.g., misconfigured TLS, insufficient governance policies) to pass validation; (b) Defense evasion — security guardrails that would otherwise block the attacker's operations are silently bypassed, enabling malicious deployments to proceed; (c) Confidentiality/availability — because integrity checkpoints are undermined, downstream systems may accept and run the attacker's code or configuration, potentially leading to data access or denial-of-service in adjacent automated workflows. The CVSS severity of 9.8 reflects the fact that evidence suppression of this kind can pivot into full host or account compromise in CI/CD-integrated environments.

Impact Assessment

The business and technical impact of CVE-2026-82855 is severe for any organization using the @hulumi/policies package in CI/CD deployment workflows, multi-tenant infrastructure, or Cloudflare-integrated governance pipelines. The vulnerability allows an unauthenticated remote attacker to disable the core assurance mechanism without leaving a trace in the target resource's compliance history, since only unrelated evidence is submitted and the validator records a passing result.

• Confidentiality Impact: High. Attacker-controlled code or configurations can bypass governance gates, potentially granting access to protected services or data in downstream deployment stages.
• Integrity Impact: High. The entire evidence validation chain loses meaning. Security attestation, compliance reporting, and policy enforcement can all be spoofed.
• Availability Impact: High. Downstream systems that rely on validation results may be manipulated, potentially allowing resource exhaustion or forced denial of service.

The blast radius is constrained to deployments using this specific package version (before 1.3.2), but within those deployments, the scope includes all resources validated by the affected Cloudflare and deployment-governance validators. Given that these validators likely run at the gate of production-promoting pipelines, compromise of one validation step can lead to full production-environment impact. The CVSS vector AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H confirms the unchained, unauthenticated, low-complexity nature of exploitation.

Organizations with strict compliance mandates (SOC 2, PCI-DSS, ISO 27001) should also note that a bypass of governance validators could invalidate compliance attestations, triggering audit failures and regulatory exposure even in the absence of active exploitation.

Detection Guidance

Sigma Rule

The following Sigma rule detects anomalous patterns of validation requests where evidence references a resource differing from the target resource. It is based on generalized log fields for policy-validation events and should be adapted to the exact logging format of the deployment tool.

title: Evidence Validation Bypass - Cross-Resource Evidence Submission
id: 3c7e193f-a2e4-4b9c-9d42-55f621f9a0c7
status: experimental
description: >
  Detects validation requests where the resource being validated differs
  from the resource referenced in the submitted compliance evidence,
  indicating a potential CVE-2026-82855 exploitation attempt.
author: Valtersit Threat Intelligence
date: 2026-06-01
logsource:
  category: application
  product: hulumi_policies
  definition: >
    Requires logging of policy-validation events including target resource
    identifier and evidence source identifier.
detection:
  selection:
    event_type: policy_validation
  correlation:
    - target_resource_zone: '*'
      evidence_resource_zone: '*'
    - target_resource_hostname: '*'
      evidence_resource_hostname: '*'
    - target_resource_origin: '*'
      evidence_resource_origin: '*'
    - target_resource_repository: '*'
      evidence_resource_repository: '*'
  condition: >-
    selection and
    (target_resource_zone != evidence_resource_zone or
     target_resource_hostname != evidence_resource_hostname or
     target_resource_origin != evidence_resource_origin or
     target_resource_repository != evidence_resource_repository)
  timeframe: 5m
level: high
falsepositives:
  - Legitimate centralized compliance evidence repositories
  - Cross-resource certificate sharing in wildcard zone setups
fields:
  - src_ip
  - target_resource_zone
  - evidence_resource_zone
  - user_agent
tags:
  - attack.t1190
  - cve.2026-82855

YARA Rule

The following YARA rule detects strings or binary patterns commonly associated with the exploitation workflow when inspecting HTTP bodies, request logs, or captured evidence files. It flags the simultaneous presence of target and unrelated evidence references.

rule CVE_2026_82855_Evidence_Substitution
{
    meta:
        author = "Valtersit Threat Intelligence"
        description = "Detects evidence-substitution patterns in validation traffic for CVE-2026-82855"
        date = "2026-06-01"
        severity = "high"
        cve = "CVE-2026-82855"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-82855"

    strings:
        $s_validate = "validate" ascii nocase
        $s_evidence = "evidence" ascii nocase
        $s_policy = "policy" ascii nocase
        $s_bypass_marker1 = "compliance" ascii nocase
        $s_zone = "zone" ascii nocase
        $s_hostname = "hostname" ascii nocase
        $s_origin = "origin" ascii nocase
        $s_repo = "repository" ascii nocase
        $s_deploy = "deployment" ascii nocase
        $s_event_type = "event_type" ascii nocase
        $s_suppression = "suppress" ascii nocase

    condition:
        uint16(0) == 0x0B00 and  // placeholder for HTTP/2 or binary protocol check
        # of ($s_validate, $s_evidence, $s_policy) >= 2 and
        any of ($s_zone, $s_hostname, $s_origin, $s_repo) and
        any of ($s_deploy, $s_suppression, $s_bypass_marker1) and
        filesize < 500KB
}

Suricata IDS Rule

alert http any any -> any any (
    msg:"CVE-2026-82855 Attempted Evidence Validation Bypass";
    flow:established,to_server;
    content:"validate";
    nocase;
    http_uri;
    content:"evidence";
    nocase;
    http_client_body;
    pcre:"/(zone|hostname|origin|repository)[\"']?\s*[:=]\s*[\"'][^\"']+[\"']/i";
    classtype:attempted-admin;
    sid:2026828550;
    rev:1;
    metadata:created_at 2026-06-01, updated_at 2026-06-01, cve CVE-2026-82855;
)

Elastic Detection

any where
  event.category == "api" and
  event.action == "policy-validation" and
  (
    (target.resource.zone != "" and evidence.resource.zone != "" and
     target.resource.zone != evidence.resource.zone) or
    (target.resource.hostname != "" and evidence.resource.hostname != "" and
     target.resource.hostname != evidence.resource.hostname) or
    (target.resource.origin != "" and evidence.resource.origin != "" and
     target.resource.origin != evidence.resource.origin) or
    (target.resource.repository != "" and evidence.resource.repository != "" and
     target.resource.repository != evidence.resource.repository)
  ) and
  event.outcome == "success"

Splunk SPL Query

index=policy_engine sourcetype=hulumi_validation earliest=-24h
| where isnotnull(target_resource_zone) AND isnotnull(evidence_resource_zone)
| where (target_resource_zone != evidence_resource_zone)
     OR (target_resource_hostname != evidence_resource_hostname)
     OR (target_resource_origin != evidence_resource_origin)
     OR (target_resource_repository != evidence_resource_repository)
| stats count by src_ip, target_resource_zone, evidence_resource_zone, user_agent
| sort -count
| rename src_ip as "Source IP", count as "Anomalous Request Count",
         target_resource_zone as "Target Zone", evidence_resource_zone as "Evidence Zone"

Wazuh OSSEC Rule

<group name="hulumi_policies,">
  <rule id="102855" level="12" frequency="3" timeframe="120">
    <decoded_as>json</decoded_as>
    <field name="event_type">^policy_validation$</field>
    <description>CVE-2026-82855: Cross-resource evidence submission detected - possible evidence validation bypass</description>
    <group>attack.t1190,</group>
    <mitre>
      <id>T1190</id>
    </mitre>
    <var name="target_resource_zone">.*</var>
    <var name="evidence_resource_zone">.*</var>
    <field name="target_resource_zone">.+</field>
    <field name="evidence_resource_zone">.+</field>
    <different_field>target_resource_zone,evidence_resource_zone</different_field>
    <options>no_full_log</options>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence for this CVE is rated 2/4 (CLAIMED — a single source, OSV, claims a fix exists, but it has not been independently confirmed). The OSV package entry lists the affected package as @hulumi/policies with a range of 0 → unfixed, suggesting the patch metadata may be incomplete or the fixed version may not yet be fully propagated across package registries.

1) Immediate Mitigations (Compensating Controls):

• Network segmentation: Restrict access to validation/governance endpoints to trusted IP ranges, CI/CD runner subnets, and authenticated jump hosts only. Do not expose these validators to the broad internet, since CVSS AV:N indicates remote exploitation potential.
• Layer-7 filtering: Deploy a WAF or reverse proxy that inspects validation requests for evidence-to-resource mismatches. Create deny-list rules for requests where the evidence resource field differs from the target resource field.
• Manual verification for high-value resources: For critical production zones and repositories, add a human-approval gate that requires a login and manual review of evidence provenance before promotion. This does not fix the vulnerability but breaks the automated exploitation chain.
• Input hardening: If feasible, modify the deployment pipeline to inject a signed, immutable metadata header into each validation request containing the true target resource identifier. Reject any request where the header does not match the evidence's resource.

2) Patch and Upgrade Steps:

• Upgrade @hulumi/policies to version 1.3.2 or later immediately. This is the version referenced by the OSV patch claim as containing the fix.
• Verify the upgrade through the npm registry: npm view @hulumi/policies versions and confirm the latest version is >1.3.2.
• After upgrade, run a regression test suite on the validators to confirm that cross-resource evidence is now rejected.
• Given patch confidence of 2/4, treat the fix as provisional: subscribe to the OSV feed for this package and monitor for further advisory updates. Independently test the vulnerability by attempting cross-zone evidence submission against a staging environment after the upgrade.

3) Long-Term Hardening:

• Adopt a checker framework: Use policy engines that bind evidence to resource identities cryptographically (e.g., signed attestations) rather than relying on the policy package's internal association logic.
• Audit trail enforcement: Ensure that all validation decisions, including evidence provenance metadata, are permanently logged to a tamper-evident log. This turns future bypass attempts into detectable events.
• Red-team validation: Include this attack pattern in the organization's security assurance testing; verify at regular intervals that the validator rejects cross-resource evidence.
• Scope review: Audit all other validators in the deployment-governance stack for similar evidence-association weaknesses, using CWE-693 as the reference classification.

References

1. NVD Entry for CVE-2026-82855 — https://nvd.nist.gov/vuln/detail/CVE-2026-82855 (primary authoritative source for CVSS score, description, and CWE-693 classification).
2. OSV Vulnerability Database — https://osv.dev/vulnerability/ (patch source reference; single-source claim of a fix in @hulumi/policies version 1.3.2).
3. CWE-693: Protection Mechanism Failure — https://cwe.mitre.org/data/definitions/693.html (weakness classification reference explaining the underlying failure pattern).
4. CISA Known Exploited Vulnerabilities (KEV) Catalog — https://www.cisa.gov/known-exploited-vulnerabilities-catalog (confirms CVE-2026-82855 is NOT currently listed in the KEV; no known exploitation in the wild).
5. MITRE ATT&CK Technique T1190: Exploit Public-Facing Application — https://attack.mitre.org/techniques/T1190/ (tactical alignment for detection rules).

Threat Actor Activity: No known threat actor campaigns, exploit-in-the-wild evidence, or public proof-of-concept code have been reported for CVE-2026-82855 as of the report date. The absence of CISA KEV inclusion and lack of Nuclei templates indicates a lack of large-scale automated exploitation; however, the low EPSS score (0.00326) should not be interpreted as low risk—it reflects the lack of publicly available exploit artifacts, not the exploitability of the flaw. The vulnerability's unauthenticated, remote, low-complexity profile makes it highly likely to be weaponized once a PoC circulates.