# CVE-2026-42159: Flowsint: Stored XSS in description of node

> A remote attacker can inject malicious HTML into node descriptions, leading to stored XSS when viewed by other users.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N`)
- **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:** No
- **Published:** 14 May 2026
- **Updated:** 14 May 2026
- **Also known as:** GHSA-w233-5mmx-cr7x

## What is CVE-2026-42159?

CVE-2026-42159 is a medium-severity cross-site scripting vulnerability in reconurge flowsint, published on 14 May 2026. 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

Flowsint is an open-source OSINT graph exploration tool designed for cybersecurity investigation, transparency, and verification. Prior to 1.2.3, Flowsint allows a user to create investigations, which are used to manage sketches and analyses. Sketches have controllable graphs, which are comprised of nodes and relationships. The sketches contain information on an OSINT target (usernames, websites, etc) within these nodes and relationships. A remote attacker can create a node with a malicious description that contains arbitrary HTML. When the node is selected, it will render the arbitrary HTML, potentially triggering stored XSS. This vulnerability is fixed in 1.2.3.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-42159?

It affects 1 product.


Products: Flowsint Flowsint.

## How do I fix CVE-2026-42159?

No fix has been published for CVE-2026-42159 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-42159 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42159 exists.

## Other vulnerabilities in reconurge flowsint

- [CVE-2026-32311](https://insights.sbomify.com/CVE-2026-32311/): Command Injection and Docker container escape allows root on host machine (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42159 and fix it if it is affected.

What it is: CVE-2026-42159 is a medium-severity cross-site scripting vulnerability in reconurge flowsint, published on 14 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42159 exists.

Affected product: reconurge flowsint. 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-2026-42159/ (Markdown: https://insights.sbomify.com/CVE-2026-42159/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42159
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42159
- OSV: https://osv.dev/vulnerability/CVE-2026-42159

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42159/
Summaries are generated and may contain mistakes; the official description above is the record.