# CVE-2026-34043: Serialize JavaScript has CPU Exhaustion Denial of Service via crafted array-like objects

> Attackers can cause CPU exhaustion and service hang by passing crafted array-like objects to the serialize-javascript library.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 31 Mar 2026
- **Updated:** 31 Mar 2026
- **Also known as:** CLEANSTART-2026-EZ44935, CLEANSTART-2026-GV24243, CLEANSTART-2026-OD19905, CLSA-2026-1776645371, CLSA-2026-1776645372, DEBIAN-CVE-2026-34043, GHSA-qj8w-gfj5-8c6v, MINI-6g5g-23xw-jfpv, MINI-96xg-4mmg-4mmx, MINI-9xx2-j2x5-9fq8, MINI-c465-hpww-q2qj, MINI-j745-w622-9r4r, MINI-v768-22g8-6xxp, MINI-x9cq-3qc8-pc8c, ROOT-APP-NPM-CVE-2026-34043, UBUNTU-CVE-2026-34043

## What is CVE-2026-34043?

CVE-2026-34043 is a medium-severity denial of service vulnerability in yahoo serialize-javascript, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Serialize JavaScript to a superset of JSON that includes regular expressions and functions. Prior to version 7.0.5, there is a Denial of Service (DoS) vulnerability caused by CPU exhaustion. When serializing a specially crafted "array-like" object (an object that inherits from Array.prototype but has a very large length property), the process enters an intensive loop that consumes 100% CPU and hangs indefinitely. This issue has been patched in version 7.0.5.

Weakness: CWE-834 (Excessive Iteration), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-34043?

2 open source packages ship an affected version, including serialize-javascript. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `serialize-javascript` | npm | From 5.0.0 | 7.0.5 |
| `serialize-javascript` | npm | From 5.0.0 | 7.0.5 |

Products: Yahoo Serialize.

## How do I fix CVE-2026-34043?

Upgrade serialize-javascript to 7.0.5 or later.

## Is CVE-2026-34043 being exploited?

There is no known exploitation of CVE-2026-34043 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34043 and fix it if it is affected.

What it is: CVE-2026-34043 is a medium-severity denial of service vulnerability in yahoo serialize-javascript, published on 31 Mar 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 CVE-2026-34043 in the wild and no public exploit code.

Affected packages and fixed versions:
- serialize-javascript (npm): affected from 5.0.0; fixed in 7.0.5
- serialize-javascript (npm): affected from 5.0.0; fixed in 7.0.5

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-2026-34043/ (Markdown: https://insights.sbomify.com/CVE-2026-34043/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34043
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34043
- OSV: https://osv.dev/vulnerability/CVE-2026-34043

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34043/
Summaries are generated and may contain mistakes; the official description above is the record.