# CVE-2025-45526: Denial of service in microlight

> An attacker can cause browser crashes or unresponsiveness by tricking users into visiting a page with excessively large content in microlight elements.

- **Severity:** Low 2.9 (`CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 17 Jun 2025
- **Updated:** 26 Jun 2025

## What is CVE-2025-45526?

CVE-2025-45526 is a low-severity denial of service vulnerability in asvd microlight, published on 17 Jun 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A denial of service (DoS) vulnerability has been identified in the JavaScript library microlight version 0.0.7. This library, used for syntax highlighting, does not limit the size of textual content it processes in HTML elements with the microlight class. When excessively large content (e.g., 100 million characters) is processed, the reset function in microlight.js consumes excessive memory and CPU resources, causing browser crashes or unresponsiveness. An attacker can exploit this vulnerability by tricking a user into visiting a malicious web page containing a microlight element with large content, resulting in a denial of service. NOTE: this is disputed by multiple parties because a large amount of memory and CPU resources is expected to be needed for content of that size.

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

## Which versions are affected by CVE-2025-45526?


## How do I fix CVE-2025-45526?

No fix has been published for CVE-2025-45526 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-45526 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-45526 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-45526 and fix it if it is affected.

What it is: CVE-2025-45526 is a low-severity denial of service vulnerability in asvd microlight, published on 17 Jun 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-45526 exists.

Affected product: asvd microlight. 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-2025-45526/ (Markdown: https://insights.sbomify.com/CVE-2025-45526/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-45526
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-45526
- OSV: https://osv.dev/vulnerability/CVE-2025-45526

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From sbomify Insights: https://insights.sbomify.com/CVE-2025-45526/
Summaries are generated and may contain mistakes; the official description above is the record.