Affected: CleanStart: argo-workflows

Security vulnerability affects the argo-workflows package. Immutable.

Immutable.js provides many Persistent Immutable data structures. Prior to 4.3.9 and 5.1.8, Immutable.Map and Immutable.Set keep keys that share the same 32-bit hash in a HashCollisionNode collision bucket that is scanned linearly, allowing an attacker who controls keys inserted into a Map, such as through Immutable.Map(obj), Immutable.fromJS(obj), state.merge(userObject), or mergeDeep, to craft many colliding keys and degrade insertion and lookup to consume disproportionate CPU. This issue is fixed in versions 4.3.9 and 5.1.8.

Affected: npm: immutable

## Summary

`Immutable.Map` and `Immutable.Set` keep keys that share the same 32-bit hash in a collision bucket that is scanned linearly. The string hash is public and deterministic, so an attacker who controls the **keys** inserted into a Map can craft many keys that all collide, degrading insertion and lookup from amortized O(1) to O(n) per operation — and O(n²) to build or read the whole set. A small, attacker-shaped payload can therefore consume disproportionate CPU and, on a single-threaded runtime such as Node.js, stall the event loop and deny service.

## Details

The string hash uses the JVM-style polynomial `hashed = (31 * hashed + charCode) | 0`. Strings such as `"Aa"` and `"BB"` hash to the same value (`65*31+97 == 66*31+66 == 2112`), and concatenating such blocks yields `2^n` distinct strings sharing one hash (40 characters ⇒ >1,000,000 colliding keys). All such keys route to a single `HashCollisionNode`, whose `get`/`update` walk the entire bucket testing `is()`. There is no per-process salt, so the colliding set is fully precomputable from the open-source algorithm.

## Proof of concept

Inserting N colliding keys (e.g. via `Immutable.Map(obj)` / `Immutable.fromJS(obj)`) is O(N²). Measured on one machine, ~8,000 colliding keys take ~0.7 s to build and ~0.6 s to read, scaling ×4 per doubling; ~16,000 keys exceed several seconds.

## Impact

CPU-bound denial of service in applications that ingest attacker-controlled object **keys** into Immutable structures, e.g…

Affected: Ubuntu:20.04:LTS: node-immutable, Ubuntu:22.04:LTS: node-immutable, Ubuntu:24.04:LTS: node-immutable, Ubuntu:25.10: node-immutable, Ubuntu:26.04:LTS: node-immutable

Immutable.js provides many Persistent Immutable data structures. Prior to 4.3.9 and 5.1.8, Immutable.Map and Immutable.Set keep keys that share the same 32-bit hash in a HashCollisionNode collision bucket that is scanned linearly, allowing an attacker who controls keys inserted into a Map, such as through Immutable.Map(obj), Immutable.fromJS(obj), state.merge(userObject), or mergeDeep, to craft many colliding keys and degrade insertion and lookup to consume disproportionate CPU. This issue is fixed in versions 4.3.9 and 5.1.8.

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in IBM Tivoli Netcool/OMNIbus ausnutzen, um einen Denial of Service Angriff durchzuführen.