CVE-2025-8848: CWE-94 Improper Control of Generation of Code in danny-avila danny-avila/librechat
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.
AI Analysis
Technical Summary
CVE-2025-8848 identifies a vulnerability in the danny-avila/librechat open-source chat application, specifically version 0.7.9, where improper handling of the Accept-Language HTTP header allows an attacker to inject arbitrary HTML code into the <html lang=""> attribute of the application's web interface. This vulnerability is categorized under CWE-94, which involves improper control of code generation, leading to injection flaws. The attack vector requires a logged-in user to send a specially crafted HTTP GET request with a malicious Accept-Language header. Because the injected HTML is reflected in the response's <html> tag, this can facilitate cross-site scripting (XSS) attacks. XSS can enable attackers to execute malicious scripts in the context of the victim's browser, potentially stealing session cookies, defacing the interface, or redirecting users to malicious sites. The CVSS 3.0 base score is 4.8 (medium severity), reflecting that the attack can be performed remotely over the network (AV:N) with low attack complexity (AC:L), but requires high privileges (PR:H) and user interaction (UI:R). The scope is changed (S:C), indicating that the vulnerability affects resources beyond the initially vulnerable component. No patches or known exploits are currently available, but the vulnerability's presence in a communication platform used for chat can pose risks to confidentiality and integrity of user data. The lack of patch availability necessitates proactive mitigation strategies. The vulnerability's exploitation requires authentication, which limits exposure to external unauthenticated attackers but still poses a risk from insider threats or compromised accounts. The injection point in the Accept-Language header is unusual, highlighting the need for strict input validation on all HTTP headers, not just typical user input fields. This vulnerability underscores the importance of secure coding practices in web applications, especially those handling user-generated content or headers that influence page rendering.
Potential Impact
For European organizations, the impact of CVE-2025-8848 primarily concerns the confidentiality and integrity of user data within the librechat platform. Successful exploitation could allow attackers to perform XSS attacks, leading to session hijacking, credential theft, or unauthorized actions performed on behalf of legitimate users. This can result in data breaches, loss of user trust, and potential regulatory penalties under GDPR if personal data is compromised. Availability is less impacted as the vulnerability does not enable denial of service. However, the reputational damage and operational disruption from a successful attack could be significant. Organizations using librechat for internal or customer communications may face increased risk of insider threats or targeted attacks exploiting this vulnerability. Since exploitation requires authenticated access, the threat is more pronounced in environments with weak access controls or where user credentials are easily compromised. The vulnerability also raises concerns about the security posture of open-source communication tools, which are increasingly adopted across European enterprises and public sector organizations. Without timely remediation, attackers could leverage this vulnerability to escalate privileges or move laterally within networks, especially in sectors with high-value targets such as finance, healthcare, and government.
Mitigation Recommendations
To mitigate CVE-2025-8848, organizations should implement strict input validation and sanitization on the Accept-Language HTTP header to prevent injection of malicious HTML. This includes encoding or stripping out any HTML or script tags before reflecting header values in responses. Applying a robust Content Security Policy (CSP) can help limit the impact of potential XSS by restricting script execution and resource loading to trusted sources. Monitoring web server logs for unusual or malformed Accept-Language headers can aid in early detection of exploitation attempts. Since no official patch is currently available, consider deploying web application firewalls (WAFs) with custom rules to block suspicious header content. Review and enforce strong authentication and session management controls to reduce the risk posed by compromised accounts. Additionally, conduct security code reviews and penetration testing focused on header injection vectors. Engage with the librechat community or vendor for updates and patches, and plan for timely application of fixes once released. Educate users and administrators about the risks of XSS and the importance of cautious handling of links and inputs within the chat platform. Finally, isolate critical communication systems to limit lateral movement in case of compromise.
Affected Countries
Germany, France, Netherlands, United Kingdom, Italy, Spain
CVE-2025-8848: CWE-94 Improper Control of Generation of Code in danny-avila danny-avila/librechat
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.
AI-Powered Analysis
Technical Analysis
CVE-2025-8848 identifies a vulnerability in the danny-avila/librechat open-source chat application, specifically version 0.7.9, where improper handling of the Accept-Language HTTP header allows an attacker to inject arbitrary HTML code into the <html lang=""> attribute of the application's web interface. This vulnerability is categorized under CWE-94, which involves improper control of code generation, leading to injection flaws. The attack vector requires a logged-in user to send a specially crafted HTTP GET request with a malicious Accept-Language header. Because the injected HTML is reflected in the response's <html> tag, this can facilitate cross-site scripting (XSS) attacks. XSS can enable attackers to execute malicious scripts in the context of the victim's browser, potentially stealing session cookies, defacing the interface, or redirecting users to malicious sites. The CVSS 3.0 base score is 4.8 (medium severity), reflecting that the attack can be performed remotely over the network (AV:N) with low attack complexity (AC:L), but requires high privileges (PR:H) and user interaction (UI:R). The scope is changed (S:C), indicating that the vulnerability affects resources beyond the initially vulnerable component. No patches or known exploits are currently available, but the vulnerability's presence in a communication platform used for chat can pose risks to confidentiality and integrity of user data. The lack of patch availability necessitates proactive mitigation strategies. The vulnerability's exploitation requires authentication, which limits exposure to external unauthenticated attackers but still poses a risk from insider threats or compromised accounts. The injection point in the Accept-Language header is unusual, highlighting the need for strict input validation on all HTTP headers, not just typical user input fields. This vulnerability underscores the importance of secure coding practices in web applications, especially those handling user-generated content or headers that influence page rendering.
Potential Impact
For European organizations, the impact of CVE-2025-8848 primarily concerns the confidentiality and integrity of user data within the librechat platform. Successful exploitation could allow attackers to perform XSS attacks, leading to session hijacking, credential theft, or unauthorized actions performed on behalf of legitimate users. This can result in data breaches, loss of user trust, and potential regulatory penalties under GDPR if personal data is compromised. Availability is less impacted as the vulnerability does not enable denial of service. However, the reputational damage and operational disruption from a successful attack could be significant. Organizations using librechat for internal or customer communications may face increased risk of insider threats or targeted attacks exploiting this vulnerability. Since exploitation requires authenticated access, the threat is more pronounced in environments with weak access controls or where user credentials are easily compromised. The vulnerability also raises concerns about the security posture of open-source communication tools, which are increasingly adopted across European enterprises and public sector organizations. Without timely remediation, attackers could leverage this vulnerability to escalate privileges or move laterally within networks, especially in sectors with high-value targets such as finance, healthcare, and government.
Mitigation Recommendations
To mitigate CVE-2025-8848, organizations should implement strict input validation and sanitization on the Accept-Language HTTP header to prevent injection of malicious HTML. This includes encoding or stripping out any HTML or script tags before reflecting header values in responses. Applying a robust Content Security Policy (CSP) can help limit the impact of potential XSS by restricting script execution and resource loading to trusted sources. Monitoring web server logs for unusual or malformed Accept-Language headers can aid in early detection of exploitation attempts. Since no official patch is currently available, consider deploying web application firewalls (WAFs) with custom rules to block suspicious header content. Review and enforce strong authentication and session management controls to reduce the risk posed by compromised accounts. Additionally, conduct security code reviews and penetration testing focused on header injection vectors. Engage with the librechat community or vendor for updates and patches, and plan for timely application of fixes once released. Educate users and administrators about the risks of XSS and the importance of cautious handling of links and inputs within the chat platform. Finally, isolate critical communication systems to limit lateral movement in case of compromise.
Affected Countries
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Technical Details
- Data Version
- 5.1
- Assigner Short Name
- @huntr_ai
- Date Reserved
- 2025-08-10T18:16:29.790Z
- Cvss Version
- 3.0
- State
- PUBLISHED
Threat ID: 68f8e49237b5c18bc820c5ca
Added to database: 10/22/2025, 2:05:06 PM
Last enriched: 10/22/2025, 2:19:37 PM
Last updated: 10/29/2025, 11:39:10 PM
Views: 26
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