# CVE-2020-26303: GHSL-2020-289: Regular Expression Denial of Service (ReDoS) in insane

> An attacker can cause a denial of service in applications using the insane HTML sanitizer library via specially crafted input triggering ReDoS.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/U:Green`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 Oct 2024
- **Updated:** 28 Oct 2024
- **Also known as:** GHSA-w455-mfq9-hf74

## What is CVE-2020-26303?

CVE-2020-26303 is a high-severity denial of service vulnerability in bevacqua insane, published on 26 Oct 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

insane is a whitelist-oriented HTML sanitizer. Versions 2.6.2 and prior contain one or more regular expressions that are vulnerable to Regular Expression Denial of Service (ReDoS). As of time of publication, no known patches are available.

Weakness: CWE-1333 (Inefficient Regular Expression Complexity)

## Which versions are affected by CVE-2020-26303?

2 open source packages ship an affected version, including insane. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `insane` | npm | All versions to 2.6.2 | None |
| `insane` | npm | All versions to 2.6.2 | None |

Products: Bevacqua Insane.

## How do I fix CVE-2020-26303?

No fix has been published for CVE-2020-26303 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-26303 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-26303 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-26303 and fix it if it is affected.

What it is: CVE-2020-26303 is a high-severity denial of service vulnerability in bevacqua insane, published on 26 Oct 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-26303 exists.

Affected packages and fixed versions:
- insane (npm): affected all versions up to 2.6.2; no fix listed
- insane (npm): affected all versions up to 2.6.2; no fix listed

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-2020-26303/ (Markdown: https://insights.sbomify.com/CVE-2020-26303/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-26303
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-26303
- OSV: https://osv.dev/vulnerability/CVE-2020-26303

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-26303/
Summaries are generated and may contain mistakes; the official description above is the record.