# GHSA-hx4r-w6wj-j8fg: devalue: Residual sparse-array CPU amplification in uneval

> An attacker can cause CPU exhaustion and event-loop blocking in applications using the devalue library by passing crafted sparse arrays to the uneval function.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Oct 2026

## What is GHSA-hx4r-w6wj-j8fg?

GHSA-hx4r-w6wj-j8fg is a denial of service vulnerability in devalue, published on 1 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

`uneval` performs synchronous work proportional to a sparse array's declared length. An application that passes attacker-influenced sparse values to `uneval` can suffer event-loop blocking. Since attacker-controlled creation of sparse arrays is so difficult, this vulnerability is very difficult to exploit.

## Which versions are affected by GHSA-hx4r-w6wj-j8fg?

2 open source packages ship an affected version, including devalue.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `devalue` | npm | All versions | 5.9.3 |
| `devalue` | npm | All versions | 5.9.3 |

## How do I fix GHSA-hx4r-w6wj-j8fg?

Upgrade devalue to 5.9.3 or later.

## Is GHSA-hx4r-w6wj-j8fg being exploited?

There is no known exploitation of GHSA-hx4r-w6wj-j8fg in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-hx4r-w6wj-j8fg and fix it if it is affected.

What it is: GHSA-hx4r-w6wj-j8fg is a denial of service vulnerability in devalue, published on 1 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of GHSA-hx4r-w6wj-j8fg in the wild and no public exploit code.

Affected packages and fixed versions:
- devalue (npm): affected all versions; fixed in 5.9.3
- devalue (npm): affected all versions; fixed in 5.9.3

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/GHSA-hx4r-w6wj-j8fg/ (Markdown: https://insights.sbomify.com/GHSA-hx4r-w6wj-j8fg/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-hx4r-w6wj-j8fg

---
From sbomify Insights: https://insights.sbomify.com/GHSA-hx4r-w6wj-j8fg/
Summaries are generated and may contain mistakes; the official description above is the record.