# CVE-2026-102992: piscina: Prototype-pollution gadget in ThreadPool.options allows RCE via execArgv / loadBalancer / env

> Prototype pollution in piscina allows attackers to inject code into worker threads via inherited options, leading to remote code execution.

- **Severity:** Critical 9.2 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Sep 2026
- **Updated:** 30 Sep 2026
- **Also known as:** AZL-105657, CLSA-2026-1790888307, CLSA-2026-1790937670, CLSA-2026-1791028065, CLSA-2026-1792472733, ECHO-6c5e-2e46-3d72, GHSA-67c8-pqhq-4rmx, MINI-2hwq-wgcw-w3hr, MINI-868p-v299-778h, MINI-mv9c-hpmg-cwm3, MINI-p8cp-3pmw-xvqp, MINI-rq43-f22r-7qw7, MINI-wrx5-mfgw-v666, ROOT-APP-NPM-CVE-2026-102992

## What is CVE-2026-102992?

CVE-2026-102992 is a critical code injection vulnerability in piscinajs piscina, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

piscina is a node.js worker pool implementation. Prior to 4.9.4, 5.3.2, and 6.0.0-rc.5, Piscina stores ThreadPool.options in src/index.ts as a plain object that inherits from Object.prototype. Applications with a separate prototype-pollution primitive can therefore supply inherited values for security-sensitive options that do not have own defaults. An inherited execArgv value is passed to the Node.js Worker constructor and can preload attacker-controlled code in worker threads, an inherited loadBalancer function can execute during task scheduling, and inherited env values can alter worker environments. This issue is fixed in versions 4.9.4, 5.3.2, and 6.0.0-rc.5.

Weakness: CWE-1321 (Improperly Controlled Modification of Object Prototype Attributes)

## Which versions are affected by CVE-2026-102992?

6 open source packages ship an affected version, including piscina.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `piscina` | npm | All versions | 4.9.4 |
| `piscina` | npm | All versions | 4.9.4 |
| `piscina` | npm | From 5.0.0 | 5.3.2 |
| `piscina` | npm | From 5.0.0 | 5.3.2 |
| `piscina` | npm | From 6.0.0-rc.1 | 6.0.0-rc.5 |
| `piscina` | npm | From 6.0.0-rc.1 | 6.0.0-rc.5 |

## How do I fix CVE-2026-102992?

Upgrade piscina to a fixed version for your release line: 4.9.4, 5.3.2 or 6.0.0-rc.5.

## Is CVE-2026-102992 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-102992 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-102992 and fix it if it is affected.

What it is: CVE-2026-102992 is a critical code injection vulnerability in piscinajs piscina, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-102992 exists.

Affected packages and fixed versions:
- piscina (npm): affected all versions; fixed in 4.9.4
- piscina (npm): affected all versions; fixed in 4.9.4
- piscina (npm): affected from 5.0.0; fixed in 5.3.2
- piscina (npm): affected from 5.0.0; fixed in 5.3.2
- piscina (npm): affected from 6.0.0-rc.1; fixed in 6.0.0-rc.5
- piscina (npm): affected from 6.0.0-rc.1; fixed in 6.0.0-rc.5

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-102992/ (Markdown: https://insights.sbomify.com/CVE-2026-102992/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-102992
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-102992
- OSV: https://osv.dev/vulnerability/CVE-2026-102992

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-102992/
Summaries are generated and may contain mistakes; the official description above is the record.