# CVE-2026-90957: MISP: Stored XSS via Inline-Served SVG Organisation Logos and Report Pictures

> Attackers can execute arbitrary scripts on the MISP origin via malicious SVG files, potentially stealing user sessions and data.

- **Severity:** Medium 5.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 14 Sep 2026
- **Updated:** 14 Sep 2026
- **Also known as:** GHSA-5mp5-7f8h-r69q

## What is CVE-2026-90957?

CVE-2026-90957 is a medium-severity cross-site scripting vulnerability in MISP, published on 14 Sep 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Affected versions of MISP serve uploaded SVG images inline without a restrictive browser sandbox.

The commit explains that SVG files are XML documents rather than passive bitmap images. While scripts inside SVG do not execute when the SVG is rendered through a normal <img>, they can execute when the SVG is navigated to directly or embedded as a document. In that case, malicious <script> elements, event handlers, or javascript: URLs execute on the MISP origin with the viewer’s session.

The affected use cases include:

 - organisation SVG logos;
 - event-report SVG pictures.

Importantly, the vulnerable behavior is on the serve path, not merely the upload path: the patch notes that a malicious SVG uploaded while SVG support was enabled could remain dangerous even after uploads were later disabled.

Version affected: ≤2.5.45

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation), CWE-693 (Protection Mechanism Failure)

## Which versions are affected by CVE-2026-90957?


## How do I fix CVE-2026-90957?

No fix has been published for CVE-2026-90957 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-90957 being exploited?

There is no known exploitation of CVE-2026-90957 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90957 and fix it if it is affected.

What it is: CVE-2026-90957 is a medium-severity cross-site scripting vulnerability in MISP, published on 14 Sep 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-90957 in the wild and no public exploit code.

Affected product: MISP. 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-2026-90957/ (Markdown: https://insights.sbomify.com/CVE-2026-90957/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90957
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90957
- OSV: https://osv.dev/vulnerability/CVE-2026-90957

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90957/
Summaries are generated and may contain mistakes; the official description above is the record.