{"id":"CVE-2026-61834","aliases":["EUVD-2026-85327","GHSA-2mhw-wcx5-v3xj"],"status":"published","title":"scim-patch: Mutation of Inherited Built-in Method Objects","description":"scim-patch is a library for applying SCIM patch operations. Prior to 0.9.2, navigate() reads inherited properties and assign() uses prototype-chain membership checks while resolving attacker-controlled SCIM PATCH paths. A path or one of the dotted value keys beginning with an inherited property such as toString can therefore traverse into a shared built-in function object and add attacker-controlled properties, causing process-global mutation that may affect application logic reading inherited-method properties. This issue is fixed in version 0.9.2.","severity":{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00396,"percentile":0.34223,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-1321","CWE-915"],"published":"2026-09-23T14:02:01Z","modified":"2026-10-28T02:30:36Z","fixes":[{"ecosystem":"npm","package":"scim-patch","fixed_in":["0.9.2"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"scim-patch","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.9.2"}]}]},{"source":"osv","ecosystem":"npm","package":"scim-patch","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.9.2"}]}]}],"products":[{"vendor":"thomaspoignant","product":"scim-patch"}],"references":[{"url":"https://github.com/thomaspoignant/scim-patch/security/advisories/GHSA-2mhw-wcx5-v3xj","tags":["x_refsource_CONFIRM","exploit","advisory","web"]},{"url":"https://github.com/thomaspoignant/scim-patch/pull/1127","tags":["x_refsource_MISC","fix","web"]},{"url":"https://github.com/thomaspoignant/scim-patch/commit/c86474f7a9b16191d939f59ba94eca6c6e63044b","tags":["x_refsource_MISC","fix","web"]},{"url":"https://github.com/thomaspoignant/scim-patch/releases/tag/v0.9.2","tags":["x_refsource_MISC","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-61834","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-2mhw-wcx5-v3xj"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/61xxx/CVE-2026-61834.json","tags":["advisory"]},{"url":"https://github.com/thomaspoignant/scim-patch","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-61834","title":"scim-patch: Mutation of Inherited Built-in Method Objects","description":"scim-patch is a library for applying SCIM patch operations. Prior to 0.9.2, navigate() reads inherited properties and assign() uses prototype-chain membership checks while resolving attacker-controlled SCIM PATCH paths. A path or one of the dotted value keys beginning with an inherited property such as toString can therefore traverse into a shared built-in function object and add attacker-controlled properties, causing process-global mutation that may affect application logic reading inherited-method properties. This issue is fixed in version 0.9.2.","status":"published","published":"2026-09-23T14:02:01.131Z","modified":"2026-09-23T16:20:22.098Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-915","CWE-1321"],"updated_at":"2026-11-02T14:19:53.4444Z"}],"euvd":[{"id":"EUVD-2026-85327","description":"scim-patch is a library for applying SCIM patch operations. Prior to 0.9.2, navigate() reads inherited properties and assign() uses prototype-chain membership checks while resolving attacker-controlled SCIM PATCH paths. A path or one of the dotted value keys beginning with an inherited property such as toString can therefore traverse into a shared built-in function object and add attacker-controlled properties, causing process-global mutation that may affect application logic reading inherited-method properties. This issue is fixed in version 0.9.2.","status":"published","published":"2026-09-23T14:02:01Z","modified":"2026-09-23T16:20:22Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T17:28:00.617613Z"}],"ghsa":[{"id":"GHSA-2mhw-wcx5-v3xj","title":"scim-patch: Mutation of Inherited Built-in Method Objects","description":"## Summary\n\nIncomplete Prototype Pollution Fix Allows Mutation of Inherited Built-in Method Objects\n\n`scim-patch` blocks direct dangerous path segments such as `__proto__`, `constructor`, and `prototype`, but still traverses inherited properties when applying SCIM patch paths.\n\nAn attacker who controls a SCIM PATCH operation can use paths such as `toString.polluted` to mutate shared built-in function objects, for example `Object.prototype.toString`.\n\n## Impact\n\nA malicious patch can add attacker-controlled properties to inherited built-in method objects. The impact is narrower than direct `Object.prototype` pollution, but the mutation is process-global and may affect application logic that reads properties from inherited methods.\n\n## Details\n\nAffected code paths:\n\n- `navigate()` reads inherited properties via `schema[subPath]`\n- `assign()` uses `key in obj`, which treats inherited properties as existing\n\nBecause inherited keys are followed, safe-looking path segments such as `toString` can resolve to shared built-in objects.\n\n## PoC\n\n```js\nconst assert = require(\"node:assert/strict\");\nconst { scimPatch } = require(\"./lib/src/scimPatch\");\n\nconst victim = {\n  schemas: [\"urn:ietf:params:scim:schemas:core:2.0:User\"],\n  userName: \"alice\",\n  active: true,\n  emails: [{ value: \"alice@example.com\", primary: true }],\n  meta: { created: \"x\", lastModified: \"x\", resourceType: \"User\" }\n};\n\ntry {\n  assert.equal(({}).toString.scimPatchPolluted, undefined);\n\n  scimPatch(victim, [\n    { op: \"add\", path: \"toString.scimPatchPolluted\", value: \"polluted\" }\n  ]);\n\n  assert.equal(({}).toString.scimPatchPolluted, \"polluted\");\n  console.log(({}).toString.scimPatchPolluted);\n} finally {\n  delete Object.prototype.toString.scimPatchPolluted;\n}\n```\n\nOutput:\n\n```text\npolluted\n```\n\nA no-path operation with a dotted value key is also affected:\n\n```js\nscimPatch(victim, [\n  { op: \"add\", value: { \"toString.noPathPolluted\": \"polluted\" } }\n]);\n```\n\n## Remediation\n\nDo not traverse inherited properties while resolving patch paths. Use own-property checks such as `Object.hasOwn(obj, key)` and create missing containers only for safe own keys.\n\nKeep the existing denylist for `__proto__`, `constructor`, and `prototype` as defense in depth.","status":"published","published":"2026-09-28T14:01:15Z","modified":"2026-09-28T14:01:17Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"cwes":["CWE-915","CWE-1321"],"updated_at":"2026-11-02T14:41:22.654187Z"}],"nvd":[{"id":"CVE-2026-61834","description":"scim-patch is a library for applying SCIM patch operations. Prior to 0.9.2, navigate() reads inherited properties and assign() uses prototype-chain membership checks while resolving attacker-controlled SCIM PATCH paths. A path or one of the dotted value keys beginning with an inherited property such as toString can therefore traverse into a shared built-in function object and add attacker-controlled properties, causing process-global mutation that may affect application logic reading inherited-method properties. This issue is fixed in version 0.9.2.","status":"published","published":"2026-09-23T15:17:15.127Z","modified":"2026-09-23T17:17:15.923Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-915","CWE-1321"],"updated_at":"2026-11-02T14:12:50.703874Z"}],"osv":[{"id":"CVE-2026-61834","title":"scim-patch: Mutation of Inherited Built-in Method Objects","description":"scim-patch is a library for applying SCIM patch operations. Prior to 0.9.2, navigate() reads inherited properties and assign() uses prototype-chain membership checks while resolving attacker-controlled SCIM PATCH paths. A path or one of the dotted value keys beginning with an inherited property such as toString can therefore traverse into a shared built-in function object and add attacker-controlled properties, causing process-global mutation that may affect application logic reading inherited-method properties. This issue is fixed in version 0.9.2.","status":"published","published":"2026-09-23T14:02:01.131Z","modified":"2026-10-28T02:30:36.747286184Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"cwes":["CWE-1321","CWE-915"],"updated_at":"2026-11-02T15:45:12.933503Z"},{"id":"GHSA-2mhw-wcx5-v3xj","title":"scim-patch: Mutation of Inherited Built-in Method Objects","description":"## Summary\n\nIncomplete Prototype Pollution Fix Allows Mutation of Inherited Built-in Method Objects\n\n`scim-patch` blocks direct dangerous path segments such as `__proto__`, `constructor`, and `prototype`, but still traverses inherited properties when applying SCIM patch paths.\n\nAn attacker who controls a SCIM PATCH operation can use paths such as `toString.polluted` to mutate shared built-in function objects, for example `Object.prototype.toString`.\n\n## Impact\n\nA malicious patch can add attacker-controlled properties to inherited built-in method objects. The impact is narrower than direct `Object.prototype` pollution, but the mutation is process-global and may affect application logic that reads properties from inherited methods.\n\n## Details\n\nAffected code paths:\n\n- `navigate()` reads inherited properties via `schema[subPath]`\n- `assign()` uses `key in obj`, which treats inherited properties as existing\n\nBecause inherited keys are followed, safe-looking path segments such as `toString` can resolve to shared built-in objects.\n\n## PoC\n\n```js\nconst assert = require(\"node:assert/strict\");\nconst { scimPatch } = require(\"./lib/src/scimPatch\");\n\nconst victim = {\n  schemas: [\"urn:ietf:params:scim:schemas:core:2.0:User\"],\n  userName: \"alice\",\n  active: true,\n  emails: [{ value: \"alice@example.com\", primary: true }],\n  meta: { created: \"x\", lastModified: \"x\", resourceType: \"User\" }\n};\n\ntry {\n  assert.equal(({}).toString.scimPatchPolluted, undefined);\n\n  scimPatch(victim, [\n    { op: \"add\", path: \"toString.scimPatchPolluted\", value: \"polluted\" }\n  ]);\n\n  assert.equal(({}).toString.scimPatchPolluted, \"polluted\");\n  console.log(({}).toString.scimPatchPolluted);\n} finally {\n  delete Object.prototype.toString.scimPatchPolluted;\n}\n```\n\nOutput:\n\n```text\npolluted\n```\n\nA no-path operation with a dotted value key is also affected:\n\n```js\nscimPatch(victim, [\n  { op: \"add\", value: { \"toString.noPathPolluted\": \"polluted\" } }\n]);\n```\n\n## Remediation\n\nDo not traverse inherited properties while resolving patch paths. Use own-property checks such as `Object.hasOwn(obj, key)` and create missing containers only for safe own keys.\n\nKeep the existing denylist for `__proto__`, `constructor`, and `prototype` as defense in depth.","status":"published","published":"2026-09-28T14:01:15Z","modified":"2026-09-28T14:15:04.388935988Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"cwes":["CWE-1321","CWE-915"],"updated_at":"2026-11-02T15:46:34.700741Z"}]}}