# CVE-2026-43878: Video: Reflected XSS in plugin/Meet/iframe.php via Unescaped user and pass Parameters in JavaScript String Literal

> Reflected XSS in AVideo allows attackers to execute arbitrary JavaScript in victims' browsers via crafted URLs, requiring no authentication if a public Meet schedule exists.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A: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:** 11 May 2026
- **Updated:** 12 May 2026
- **Also known as:** GHSA-mm5f-8q57-4fc4

## What is CVE-2026-43878?

CVE-2026-43878 is a medium-severity cross-site scripting vulnerability in WWBN AVideo, published on 11 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

WWBN AVideo is an open source video platform. In versions up to and including 29.0, plugin/Meet/iframe.php echoes the attacker-controlled user and pass query parameters unescaped into a JavaScript double-quoted string literal inside a <script> block. An attacker who sends a victim to a crafted URL can break out of the string and execute arbitrary JavaScript in the victim's browser in the context of the AVideo origin. No authentication is required if a public Meet schedule exists on the target. Commit 3298ced2bcf92e4f3acff6ce9bde14edf42ecb5b contains an updated fix.

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

## Which versions are affected by CVE-2026-43878?

2 open source packages ship an affected version, including wwbn/avideo.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `wwbn/avideo` | Packagist | All versions to 29.0 | None |
| `wwbn/avideo` | Packagist | All versions to 29.0 | None |

## How do I fix CVE-2026-43878?

No fix has been published for CVE-2026-43878 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-43878 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-43878 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-43878 and fix it if it is affected.

What it is: CVE-2026-43878 is a medium-severity cross-site scripting vulnerability in WWBN AVideo, published on 11 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-2026-43878 exists.

Affected packages and fixed versions:
- wwbn/avideo (Packagist): affected all versions up to 29.0; no fix listed
- wwbn/avideo (Packagist): affected all versions up to 29.0; 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-2026-43878/ (Markdown: https://insights.sbomify.com/CVE-2026-43878/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43878
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43878
- OSV: https://osv.dev/vulnerability/CVE-2026-43878

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43878/
Summaries are generated and may contain mistakes; the official description above is the record.