CVE-2026-78180: Alibaba Fusion Next RCE Vulnerability

CVE-2026-78180 Overview

CVE-2026-78180 is a prototype pollution vulnerability in the Alibaba Fusion Next React component library up to version 1.27.34. The flaw affects the ConfigProvider.getContextProps function in components/dialog/index.tsx, which uses a deepMerge operation on the locale argument. Manipulation of this argument leads to improperly controlled modification of object prototype attributes [CWE-94]. An attacker can trigger the issue remotely without authentication or user interaction. The associated GitHub issue was closed automatically due to inactivity, indicating the flaw may remain unpatched in affected releases.

Critical Impact
Remote prototype pollution in the Dialog component's deepMerge handling can allow attackers to tamper with base object prototypes, affecting application logic, integrity, and availability.

Affected Products

Alibaba Fusion Next through version 1.27.34
Applications embedding the vulnerable ConfigProvider and Dialog components
Downstream React projects that pass user-controlled locale data into deepMerge

Discovery Timeline

2026-08-24 - CVE-2026-78180 published to NVD
2026-08-24 - Last updated in NVD database

Technical Details for CVE-2026-78180

Vulnerability Analysis

The vulnerability resides in ConfigProvider.getContextProps within components/dialog/index.tsx. The function invokes a deepMerge routine that recursively copies properties from a source object into a target. When an attacker controls the locale argument, they can supply keys such as __proto__, constructor, or prototype that traverse into Object.prototype. Any property written there becomes visible to every object in the JavaScript runtime. This class of flaw is tracked as improperly controlled modification of object prototype attributes and is categorized under [CWE-94].

Root Cause

The deepMerge implementation does not filter dangerous property names before recursing. It treats reserved keys the same as any other, which lets a caller reach the prototype chain of built-in objects. React applications using ConfigProvider typically pass localization data through configuration flows, so untrusted input can reach the sink when developers forward external data without sanitization.

Attack Vector

Exploitation occurs remotely over the network. An attacker submits crafted locale data through any input path that reaches ConfigProvider.getContextProps. Once the polluted properties land on Object.prototype, they influence subsequent object lookups across the application. Consequences include denial of service, tampering with feature flags, altering security-relevant defaults, and in some deployments enabling downstream code execution when polluted properties are later interpolated into templates or command paths. See GitHub Issue #5101 and the VulDB CVE-2026-78180 entry for additional technical context.

No verified proof-of-concept code has been published. Technical details are described in prose here in the absence of vendor-confirmed exploit code.

Detection Methods for CVE-2026-78180

Indicators of Compromise

Requests containing __proto__, constructor.prototype, or prototype keys in JSON payloads targeting endpoints that feed ConfigProvider configuration.
Unexpected default property values appearing on plain JavaScript objects at runtime, such as new keys on empty object literals.
Application errors or altered UI behavior in Dialog components following untrusted configuration updates.

Detection Strategies

Perform a dependency inventory to flag applications importing @alibaba-fusion/next at or below version 1.27.34.
Add static analysis rules that detect deepMerge calls consuming request-derived data without key filtering.
Enable runtime guards that freeze Object.prototype in non-production builds to surface pollution attempts during testing.

Monitoring Recommendations

Log and alert on HTTP request bodies containing prototype-related keys such as __proto__ or constructor.
Track anomalies in application configuration state, especially unexpected mutations of localization or Dialog options.
Correlate error spikes in React rendering paths with recent configuration change events.

How to Mitigate CVE-2026-78180

Immediate Actions Required

Audit all uses of ConfigProvider.getContextProps and remove user-controlled input from the locale argument.
Introduce input validation that rejects payloads containing __proto__, constructor, or prototype keys before merge operations.
Replace generic deepMerge calls with a safe merge utility that ignores non-own or reserved keys.

Patch Information

No vendor patch has been published at the time of NVD publication. The upstream GitHub issue was closed automatically due to inactivity. Monitor the Alibaba Fusion Next repository for a fixed release above 1.27.34 and pin dependencies until a patched version is confirmed.

Workarounds

Wrap deepMerge in a sanitizer that strips prototype-related keys from every source object before recursion.
Use Object.create(null) for configuration containers so pollution of Object.prototype does not affect them.
Call Object.freeze(Object.prototype) early in application bootstrap where compatibility allows, blocking runtime pollution attempts.

bash

# Configuration example
# Pin to a known baseline and prepare to upgrade once a fix ships
npm ls @alibaba-fusion/next
npm install @alibaba-fusion/next@1.27.34 --save-exact
# Optional: enforce a resolution policy in package.json
# "overrides": { "@alibaba-fusion/next": "1.27.34" }