# CVE-2023-4578: Error reporting methods in SpiderMonkey could have triggered an Out of Memory Exception

> An error handling flaw in SpiderMonkey could cause an unhandled Out of Memory exception, leading to a denial of service in Firefox and Thunderbird.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 11 Sep 2023
- **Updated:** 18 Dec 2025
- **Also known as:** DEBIAN-CVE-2023-4578, GHSA-phv6-6pfh-prxc, UBUNTU-CVE-2023-4578

## What is CVE-2023-4578?

CVE-2023-4578 is a medium-severity denial of service vulnerability in Mozilla Firefox, published on 11 Sep 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

When calling `JS::CheckRegExpSyntax` a Syntax Error could have been set which would end in calling `convertToRuntimeErrorAndClear`. A path in the function could attempt to allocate memory when none is available which would have caused a newly created Out of Memory exception to be mishandled as a Syntax Error. This vulnerability affects Firefox < 117, Firefox ESR < 115.2, and Thunderbird < 115.2.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2023-4578?

It affects 3 products.


Products: Mozilla Firefox, Mozilla Firefox Esr, Mozilla Thunderbird.

## How do I fix CVE-2023-4578?

Upgrade to a fixed version.

## Is CVE-2023-4578 being exploited?

There is no known exploitation of CVE-2023-4578 in the wild and no public exploit code.

## Other vulnerabilities in Mozilla Firefox

- [CVE-2019-11708](https://insights.sbomify.com/CVE-2019-11708/): Mozilla Firefox and Thunderbird Sandbox Escape (critical 10.0, exploited in the wild)
- [CVE-2010-3765](https://insights.sbomify.com/CVE-2010-3765/): Mozilla Multiple Products Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2022-26486](https://insights.sbomify.com/CVE-2022-26486/): Mozilla Firefox Use-After-Free (critical 9.6, exploited in the wild)
- [CVE-2022-26485](https://insights.sbomify.com/CVE-2022-26485/): Mozilla Firefox Use-After-Free (high 8.8, exploited in the wild)
- [CVE-2019-11707](https://insights.sbomify.com/CVE-2019-11707/): Mozilla Firefox and Thunderbird Type Confusion (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-4578 and fix it if it is affected.

What it is: CVE-2023-4578 is a medium-severity denial of service vulnerability in Mozilla Firefox, published on 11 Sep 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2023-4578 in the wild and no public exploit code.

Affected product: Mozilla Firefox. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2023-4578/ (Markdown: https://insights.sbomify.com/CVE-2023-4578/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-4578
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-4578
- OSV: https://osv.dev/vulnerability/CVE-2023-4578

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-4578/
Summaries are generated and may contain mistakes; the official description above is the record.