CWE-1321

Prototype pollution in Adobe Acrobat Reader versions 24.001.30356, 26.001.21367 and earlier enables arbitrary code execution in user context via malicious PDF files. Attack requires user interaction to open a crafted document. CVSS 9.6 (Critical) reflects network-deliverable code execution with scope change, though EPSS 0.24% (46th percentile) suggests moderate real-world exploitation probability. No public exploit identified at time of analysis.

Prototype pollution in LangSmith JavaScript/TypeScript SDK (langsmith) versions prior to 0.5.18 allows remote attackers to pollute Object.prototype via the createAnonymizer() API by supplying malicious constructor.prototype keys, bypassing an incomplete __proto__ filter. The vulnerability affects all objects in the Node.js process and can lead to information disclosure and integrity violations. No public exploit code or active exploitation has been confirmed at time of analysis.

Prototype pollution in defu npm package (≤6.1.4) allows remote attackers to override application logic by injecting __proto__ keys through unsanitized user input. The vulnerability enables authentication bypass and arbitrary property injection when applications merge untrusted JSON, database records, or configuration data using defu(). CVSS 7.5 (High) with network-accessible, low-complexity exploitation requiring no authentication. No active exploitation confirmed (not in CISA KEV), but public proof-of-concept exists in the GitHub advisory demonstrating admin privilege escalation.

Prototype pollution in Lodash 4.17.23 and earlier allows unauthenticated remote attackers to delete properties from built-in prototypes (Object.prototype, Number.prototype, String.prototype) via array-wrapped path segments in _.unset and _.omit functions, bypassing the incomplete fix for CVE-2025-13465. The vulnerability has a CVSS score of 6.5 with low integrity and availability impact; no public exploit code or active exploitation has been confirmed at time of analysis.

Prototype pollution in MikroORM's Utils.merge function allows attackers to modify JavaScript object prototypes when applications pass untrusted user input into ORM operations. Affects @mikro-orm/core npm package, enabling denial of service and potentially SQL injection when polluted properties influence query construction. No public exploit identified at time of analysis, though GitHub security advisory published by the project maintainers confirms the vulnerability class (CWE-1321).

Prototype pollution in locutus npm package version 2.0.39 through 3.0.24 allows remote attackers to bypass `Object.prototype` pollution guards via a crafted query string passed to the `parse_str` function, enabling authentication bypass, denial of service, or remote code execution in chained attack scenarios where `RegExp.prototype.test` has been previously compromised. Publicly available exploit code exists demonstrating the vulnerability; vendor-released patch available in version 3.0.25.

Prototype pollution in the locutus npm package's unserialize() function allows remote attackers to inject arbitrary properties into deserialized objects by crafting malicious PHP-serialized payloads containing __proto__ keys, enabling authorization bypass, property propagation attacks, and denial of service via method override. The vulnerability affects locutus versions prior to 3.0.25; publicly available exploit code exists demonstrating property injection, for-in propagation to real own properties, and built-in method disruption.

Prototype pollution in convict npm package version 6.2.4 allows attackers to bypass previous security fixes and pollute Object.prototype through crafted input that manipulates String.prototype.startsWith. The vulnerability affects applications processing untrusted input via convict.set() and can lead to authentication bypass, denial of service, or remote code execution if polluted properties reach dangerous sinks like eval or child_process. A working proof-of-concept exploit demonstrating the bypass technique exists in the advisory.

Prototype pollution in Mozilla's node-convict configuration library allows attackers to inject properties into Object.prototype via two unguarded code paths: config.load()/loadFile() methods that fail to filter forbidden keys during recursive merge operations, and schema initialization accepting constructor.prototype.* keys during default-value propagation. Applications using node-convict (pkg:npm/convict) that process untrusted configuration data face impacts ranging from authentication bypass to remote code execution depending on how polluted properties propagate through the application. This represents an incomplete fix for prior prototype pollution issues (GHSA-44fc-8fm5-q62h), with no public exploit identified at time of analysis.

picomatch is vulnerable to a method injection vulnerability (CWE-1321) in its POSIX_REGEX_SOURCE object that allows specially crafted POSIX bracket expressions like [[:constructor:]] to reference inherited Object.prototype methods, causing these methods to be stringified and injected into generated regular expressions. This affects all versions of the npm package picomatch prior to 2.3.2, 3.0.2, and 4.0.4, and can cause incorrect glob matching behavior leading to integrity violations where patterns match unintended filenames; while this does not enable remote code execution, it can compromise security-relevant logic in applications using glob matching for filtering, validation, or access control. The vulnerability is not listed in CISA KEV and has no widely published proof-of-concept, but patches are available from the vendor.