# CVE-2026-89253: AVideo Stored XSS via donationLink in watch page button

> Authenticated users can inject JavaScript via donation links, allowing attackers to execute code in victims' browsers, including administrators, when viewing videos.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/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:** 11 Sep 2026
- **Updated:** 11 Sep 2026
- **Also known as:** GHSA-34jx-r3p9-7pp2, GHSA-hwfm-c6x6-hx7r

## What is CVE-2026-89253?

CVE-2026-89253 is a critical cross-site scripting vulnerability in WWBN AVideo, published on 11 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

WWBN AVideo through commit c3edcc274c389816d434acadac07ee78eaf330c1 contains a stored cross-site scripting vulnerability in the user 'donationLink' profile field. User::setDonationLink() (objects/user.php) stores the value and save() validates it only with filter_var(..., FILTER_VALIDATE_URL), which accepts strings such as http://evil.example/"onmouseover=alert(document.domain)//, while getDonationLink() applies only strip_tags() and does not encode double quotes. plugin/CustomizeUser/actionButton.php echoes the value unencoded into an <a href="..."> attribute, and that button is included from view/modeYoutubeBottom.php on the watch page when the CustomizeUser option allowDonationLink is enabled. An authenticated user who updates their own profile via objects/userUpdate.json.php can therefore break out of the href attribute and inject an event handler that executes JavaScript in the browser of any visitor—including an administrator—who views the attacker's videos and interacts with (for example, hovers over) the donation button. The issue was unfixed at the time of reporting.

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

## Which versions are affected by CVE-2026-89253?


## How do I fix CVE-2026-89253?

No fix has been published for CVE-2026-89253 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-89253 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-89253 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89253 and fix it if it is affected.

What it is: CVE-2026-89253 is a critical cross-site scripting vulnerability in WWBN AVideo, published on 11 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-89253 exists.

Affected product: WWBN AVideo. 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-2026-89253/ (Markdown: https://insights.sbomify.com/CVE-2026-89253/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89253
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89253
- OSV: https://osv.dev/vulnerability/CVE-2026-89253

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-89253/
Summaries are generated and may contain mistakes; the official description above is the record.