# GHSA-wf3x-273g-mvxv: devalue: Sparse arrays emitted by uneval cause eager allocation when evaluated

> Evaluating sparse array output from devalue's uneval function can cause excessive memory allocation, leading to denial of service in consuming environments.

- **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-wf3x-273g-mvxv?

GHSA-wf3x-273g-mvxv 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

Evaluating legitimate `uneval` output for a sparse array can allocate memory proportional to its declared length. A tiny serialized value can therefore cause large memory allocation in a consuming browser/runtime. This occurs during evaluation of generated code, not in default `parse` sparse-array construction.

You would only be affected by this if you were serializing very large sparse arrays and then evaluating the results. In the general use case for `uneval` of sending data to the client, the worst that could happen is the browser tab running out of memory.

## Which versions are affected by GHSA-wf3x-273g-mvxv?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `devalue` | npm | From 1.0.0 | 5.9.3 |
| `devalue` | npm | From 1.0.0 | 5.9.3 |

## How do I fix GHSA-wf3x-273g-mvxv?

Upgrade devalue to 5.9.3 or later.

## Is GHSA-wf3x-273g-mvxv being exploited?

There is no known exploitation of GHSA-wf3x-273g-mvxv in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-wf3x-273g-mvxv and fix it if it is affected.

What it is: GHSA-wf3x-273g-mvxv 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-wf3x-273g-mvxv in the wild and no public exploit code.

Affected packages and fixed versions:
- devalue (npm): affected from 1.0.0; fixed in 5.9.3
- devalue (npm): affected from 1.0.0; 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-wf3x-273g-mvxv/ (Markdown: https://insights.sbomify.com/GHSA-wf3x-273g-mvxv/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-wf3x-273g-mvxv

---
From sbomify Insights: https://insights.sbomify.com/GHSA-wf3x-273g-mvxv/
Summaries are generated and may contain mistakes; the official description above is the record.