CVE-2025-8848 HTML Injection in Accept-Language Header in danny-avila/librechat

Medium 4.8 Published 22 Oct 2025 Updated 30 Oct 2025

Attackers can inject arbitrary HTML via the Accept-Language header, potentially leading to cross-site scripting attacks against logged-in users.

Exploited in the wild: Not known
Login needed: An administrator
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2025-8848?

CVE-2025-8848 is a medium-severity cross-site scripting vulnerability in Librechat Librechat, published on 22 Oct 2025. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

Official description

A vulnerability in danny-avila/librechat version 0.7.9 allows for HTML injection via the Accept-Language header. When a logged-in user sends an HTTP GET request with a crafted Accept-Language header, arbitrary HTML can be injected into the <html lang=""> tag of the response. This can lead to potential security risks such as cross-site scripting (XSS) attacks.

Weakness: CWE-79, CWE-94

Which versions are affected by CVE-2025-8848?

It affects 1 product.

Products include Librechat Librechat.

How do I fix CVE-2025-8848?

No fix has been published for CVE-2025-8848 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2025-8848 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-8848 exists.

Public exploit code: 1 Nuclei template.

All Librechat Librechat vulnerabilities

Sources

Also known as GHSA-xqvm-m8v9-8w9h.