CVE-2025-8848Public exploitNetwork attack vector

Cross-site scripting via unescaped Accept-Language header

Published Oct 22, 2025 · Updated Oct 30, 2025

HTML injection in LibreChat 0.7.9 allows remote authenticated users to inject markup through a crafted Accept-Language request header. The HTML response template copies the header value into the document's lang attribute without neutralizing attribute-breaking markup. A logged-in session and user interaction are required; successful script execution occurs in the responding browser and can expose or alter browser-accessible data.

CVSS severity5.4
Medium
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

HTML injection in LibreChat 0.7.9 allows remote authenticated users to inject markup through a crafted Accept-Language request header. The HTML response template copies the header value into the document's lang attribute without neutralizing attribute-breaking markup. A logged-in session and user interaction are required; successful script execution occurs in the responding browser and can expose or alter browser-accessible data.

The record

CVE
CVE-2025-8848
Published
Oct 22, 2025
Updated
Oct 30, 2025
Vendor
Danny Avila
Product
LibreChat
Classifications
CWE-79, CWE-94, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 22, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 30, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=latest

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Danny Avila · LibreChatversion=unspecified <=latest

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
4.8huntr.devCVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-94Improper Control of Generation of Code ('Code Injection')
T1059.007JavaScript/JScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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