{"id":"CVE-2026-33993","state":"PUBLISHED","title":"Locutus has Prototype Pollution via __proto__ Key Injection in unserialize()","description":"Locutus brings stdlibs of other programming languages to JavaScript for educational purposes. Prior to version 3.0.25, the `unserialize()` function in `locutus/php/var/unserialize` assigns deserialized keys to plain objects via bracket notation without filtering the `__proto__` key. When a PHP serialized payload contains `__proto__` as an array or object key, JavaScript's `__proto__` setter is invoked, replacing the deserialized object's prototype with attacker-controlled content. This enables property injection, for...in propagation of injected properties, and denial of service via built-in method override. This is distinct from the previously reported prototype pollution in `parse_str` (GHSA-f98m-q3hr-p5wq, GHSA-rxrv-835q-v5mh) — `unserialize` is a different function with no mitigation applied. Version 3.0.25 patches the issue.","publishedAt":"2026-03-27T22:14:03.495Z","updatedAt":"2026-03-30T15:45:18.660Z","severity":{"score":6.9,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["locutusjs locutus"],"affected":[{"vendor":"locutusjs","product":"locutus","versions":[{"version":"< 3.0.25","status":"affected"}]}],"references":["https://github.com/locutusjs/locutus/security/advisories/GHSA-4mph-v827-f877","https://github.com/locutusjs/locutus/pull/597","https://github.com/locutusjs/locutus/commit/345a6211e1e6f939f96a7090bfeff642c9fcf9e4","https://github.com/locutusjs/locutus/releases/tag/v3.0.25"],"weaknesses":["CWE-1321"],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/33xxx/CVE-2026-33993.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-33993","state":"PUBLISHED","datePublished":"2026-03-27T22:14:03.495Z","dateUpdated":"2026-03-30T15:45:18.660Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-03-24T22:20:06.212Z"},"containers":{"cna":{"title":"Locutus has Prototype Pollution via __proto__ Key Injection in unserialize()","descriptions":[{"lang":"en","value":"Locutus brings stdlibs of other programming languages to JavaScript for educational purposes. Prior to version 3.0.25, the `unserialize()` function in `locutus/php/var/unserialize` assigns deserialized keys to plain objects via bracket notation without filtering the `__proto__` key. When a PHP serialized payload contains `__proto__` as an array or object key, JavaScript's `__proto__` setter is invoked, replacing the deserialized object's prototype with attacker-controlled content. This enables property injection, for...in propagation of injected properties, and denial of service via built-in method override. This is distinct from the previously reported prototype pollution in `parse_str` (GHSA-f98m-q3hr-p5wq, GHSA-rxrv-835q-v5mh) — `unserialize` is a different function with no mitigation applied. Version 3.0.25 patches the issue."}],"affected":[{"vendor":"locutusjs","product":"locutus","versions":[{"version":"< 3.0.25","status":"affected"}]}],"references":[{"url":"https://github.com/locutusjs/locutus/security/advisories/GHSA-4mph-v827-f877","name":"https://github.com/locutusjs/locutus/security/advisories/GHSA-4mph-v827-f877","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/locutusjs/locutus/pull/597","name":"https://github.com/locutusjs/locutus/pull/597","tags":["x_refsource_MISC"]},{"url":"https://github.com/locutusjs/locutus/commit/345a6211e1e6f939f96a7090bfeff642c9fcf9e4","name":"https://github.com/locutusjs/locutus/commit/345a6211e1e6f939f96a7090bfeff642c9fcf9e4","tags":["x_refsource_MISC"]},{"url":"https://github.com/locutusjs/locutus/releases/tag/v3.0.25","name":"https://github.com/locutusjs/locutus/releases/tag/v3.0.25","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.9,"baseSeverity":"MEDIUM","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-1321","lang":"en","description":"CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-03-27T22:14:03.495Z"},"source":{"advisory":"GHSA-4mph-v827-f877","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-03-30T15:45:05.433846Z","id":"CVE-2026-33993","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-03-30T15:45:18.660Z"}}]}}}