CVE-2025-8848VulnerabilityPublished 22 Oct 2025Updated 30 Oct 2025

CVE-2025-8848: danny-avila/librechat · Improper Control of Generation of Code

Affects danny-avila/librechatSource CVE Database V5

Not known to be exploited · public detection template (Nuclei) · CVSS 4.8 Medium.

Data as of 26 Oct 2026, 08:30 UTC

CVSS 3.0 base score

4.8Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 39% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: High
User Interaction: Required
Scope: Changed
Confidentiality: Low
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Oct 2025
Detectable: evidence found.
nuclei template: LibreChat <= 0.7.9 - HTML Injection via Accept-Language Header
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
GitHubdanny-avila/librechat`pkg:github/danny-avila/librechat`Other threats	Affected =0.7.9	Fixed in–

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AI-suggested

To mitigate CVE-2025-8848, organizations should implement strict input validation and output encoding for all HTTP headers, especially the Accept-Language header, to prevent injection of malicious HTML or scripts. Applying Content Security Policy (CSP) headers can help reduce the impact of potential XSS attacks by restricting script execution sources. Since the vulnerability requires authenticated access, enforcing strong authentication mechanisms and monitoring for unusual user behavior can reduce exploitation risk. Organizations should monitor official danny-avila/librechat repositories and security advisories for patches or updates addressing this issue and apply them promptly once available. In the interim, consider implementing web application firewalls (WAFs) with rules to detect and block suspicious Accept-Language header values. Security awareness training for users to recognize phishing or social engineering attempts related to this vulnerability is also recommended. Finally, conduct regular security assessments and penetration tests focusing on input validation weaknesses in web applications.

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.

Impact

For European organizations using danny-avila/librechat, this vulnerability poses a risk to user confidentiality and data integrity. Successful exploitation could allow attackers to hijack user sessions, steal sensitive information, or manipulate user interactions within the chat platform. Given that exploitation requires authenticated users and user interaction, the threat is somewhat limited to insider threats or social engineering scenarios. However, in environments where librechat is used for sensitive communications, such as governmental, financial, or healthcare sectors, the impact could be significant. The vulnerability does not affect system availability but undermines trust in the platform's security. Organizations relying on librechat for internal or external communications should be aware of the potential for targeted attacks exploiting this flaw. The medium severity rating reflects the moderate risk level but should not lead to complacency, especially in high-security contexts.

CWE-94Improper Control of Generation of Code ('Code Injection') (opens in a new tab)
Base weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #10OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
Architecture and Design · Refactoring
Refactor your program so that you do not have to dynamically generate code.
Architecture and Design
Run your code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which code can be executed by your product.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Unvalidated Redirects and Forwards (opens in a new tab)
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V5.2.8 (opens in a new tab)
V5.2.5 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
Leverage Executable Code in Non-Executable Files (opens in a new tab)
Manipulating User-Controlled Variables (opens in a new tab)
Code Injection (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

huntr.com/bounties/a05ebc1f-882a-4adc-b178-d3cefa4b730e (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 31 Oct 2025, 04:37 UTC

Public exploits and detectiona Nuclei detection template

WeaknessesCWE-94

Technical details

References

Community reviews

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