CVE-2026-30962: 
JavaScript vulnerability analysis and mitigation

CVE-2026-30962 is a protected fields bypass vulnerability in Parse Server, an open-source Node.js backend platform, that allows any authenticated user to extract values from protected fields by wrapping query constraints inside logical operators. The vulnerability affects all Parse Server versions prior to 8.6.19 and versions 9.0.0 through 9.5.2-alpha.5. It was discovered by researcher 0xkakash1, coordinated by mtrezza, and publicly disclosed on March 10, 2026. The vulnerability carries a CVSS v3.1 base score of 6.5 (Medium) and a CVSS v4.0 base score of 7.1 (High) (Github Advisory, Parse Server Advisory).

The root cause is improper access control (CWE-284): Parse Server's validation logic for protected fields only inspects top-level query keys, failing to recursively examine nested sub-queries. An attacker can exploit this by wrapping a query constraint targeting a protected field inside a logical operator (e.g., $or, $and), causing the field-level protection check to be bypassed entirely. The fix, applied in the patched releases, adds recursive validation of sub-queries within logical operators, consistent with existing recursive validation patterns elsewhere in the codebase. No public proof-of-concept code has been identified at this time (Parse Server Advisory, Github Advisory).

Successful exploitation allows any authenticated user — regardless of privilege level — to query and extract values from fields designated as protected, which are intended to be inaccessible to regular users. Since all Parse Server deployments include default protected fields, every unpatched instance is affected, potentially exposing sensitive data such as user credentials, internal identifiers, or application-specific confidential fields. There is no integrity or availability impact; the vulnerability is limited to confidentiality loss (Parse Server Advisory, Github Advisory).

No public proof-of-concept exploit code has been identified, and there is no evidence of in-the-wild exploitation at the time of disclosure. The vulnerability requires only low-privilege authentication (any valid Parse Server account), making it accessible to a broad range of potential attackers. The EPSS score is approximately 0.046% (15th percentile), indicating a currently low probability of exploitation within 30 days. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog (Github Advisory).

1. Obtain authentication credentials: Register or obtain a valid account on the target Parse Server instance — any standard user account is sufficient.
2. Identify protected fields: Review the application's schema or attempt queries to enumerate fields that are normally restricted (e.g., fields returning empty or redacted values under normal queries).
3. Craft a bypass query: Construct a Parse query that wraps a constraint on a protected field inside a logical operator such as $or or $and. For example, send a query like {"$or": [{"protectedField": {"$exists": true}}]} via the Parse REST API or SDK.
4. Submit the query: Send the crafted query to the Parse Server API endpoint (e.g., POST /1/classes/ClassName) with a valid session token in the X-Parse-Session-Token header.
5. Extract field values: Parse the API response, which will include values from the protected field that would otherwise be filtered out, enabling data exfiltration (Parse Server Advisory).

• Network: Unusual API requests to Parse Server class endpoints (e.g., POST /1/classes/<ClassName>) containing logical operators ($or, $and, $nor) in the query body that reference fields not typically queried by the application.
• Logs: Parse Server access logs showing authenticated requests with query payloads containing nested logical operator structures targeting sensitive or protected field names; repeated queries from a single session token probing multiple protected fields.
• Application Behavior: Query responses returning data for fields that should be protected/empty under normal access controls, indicating a bypass is occurring.

Parse Server users should upgrade immediately to version 8.6.19 (for the 8.x branch) or 9.5.2-alpha.6 (for the 9.x alpha branch), both released on March 8, 2026, which add recursive validation of sub-queries within logical operators (Parse Server 8.6.19 Release, Parse Server 9.5.2-alpha.6 Release). For deployments unable to patch immediately, the official workaround is to implement a beforeFind trigger on affected classes that manually inspects incoming queries for protected field references within logical operator sub-queries and rejects such requests. Additionally, restricting the number of authenticated users with access to the Parse Server instance reduces the attack surface until patching is complete (Parse Server Advisory).