Bitwarden PDF File Handler Vulnerability Let Attackers Upload Malicious PDF Files
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A critical cross-site scripting (XSS) vulnerability has been discovered in the popular password manager Bitwarden, affecting versions up to 2.25.1.
The security flaw, designated as CVE-2025-5138, resides in the PDF File Handler component and allows attackers to upload malicious PDF files that can execute arbitrary code when viewed by users.
Despite early notification to the vendor, Bitwarden has not responded to the disclosure, leaving millions of users potentially vulnerable to remote attacks.
Bitwarden PDF XSS Vulnerability
The vulnerability stems from insufficient file type restrictions in Bitwarden’s Resources upload feature, which fails to properly validate uploaded PDF documents.
According to security researchers, the flaw is classified under CWE-79 (Cross-site Scripting) and has been assigned a CVSS v3.1 base score of 3.5, indicating moderate severity.
The vulnerability affects an unknown functionality within the PDF File Handler component, where user-controllable input is not properly neutralized before being placed in output that serves web pages to other users.
When attackers exploit this vulnerability, they can manipulate PDF files to inject malicious JavaScript code that executes within the context of the Bitwarden application.
The attack vector requires the attacker to have authenticated access (PR:L – Low Privileges Required) and relies on user interaction (UI:R – User Interaction Required) to trigger the malicious payload.
The vulnerability specifically impacts the integrity of the application (I:L – Low Impact on Integrity) while maintaining no direct effect on confidentiality or availability.
Risk Factors Details Affected ProductsBitwarden versions ≤ 2.25.1 (PDF File Handler component)ImpactAllows execution of arbitrary JavaScript via malicious PDFs, potentially enabling session hijacking, credential theft, or unauthorized actions within the user’s Bitwarden vault.Exploit Prerequisites1. Attacker requires authenticated access (low privileges) 2. User interaction to open malicious PDF 3. Relies on browser PDF rendering enginesCVSS 3.1 Score3.5 (Medium)
Proof of Concept
Security researcher YZS17 has published a detailed proof-of-concept (PoC) demonstrating the exploitation technique on GitHub.
The attack follows a straightforward process: first, an attacker creates a new project within Bitwarden’s interface, then uploads a specially crafted PDF file containing malicious JavaScript code.
When legitimate users subsequently open the PDF file through Google Chrome or other browsers, the embedded code executes automatically.
The PoC reveals that the vulnerability exploits the browser’s native PDF rendering capabilities, bypassing Bitwarden’s security controls.
The malicious PDF file leverages JavaScript injection techniques similar to those documented in portable data exfiltration research, where controlling HTTP hyperlinks within PDF documents can provide access to internal PDF workings.
This technique essentially creates “XSS within the bounds of a PDF document,” allowing attackers to execute arbitrary JavaScript and potentially steal sensitive information from users’ vaults.
Mitigation
Despite researchers contacting Bitwarden early in the disclosure process, the company has failed to acknowledge or respond to the vulnerability report.
This lack of communication raises concerns about Bitwarden’s incident response procedures, particularly given the company’s reputation for robust security practices outlined in their security whitepaper.
Currently, no official patches or countermeasures have been released by Bitwarden. Security experts recommend that organizations using affected versions consider replacing Bitwarden with alternative password management solutions until a fix becomes available.
Users should exercise extreme caution when opening PDF attachments within their Bitwarden vaults and avoid clicking on unknown PDF files shared through the platform.
The vulnerability discovery highlights broader security concerns regarding PDF handling in web applications, as similar injection flaws have been identified in popular PDF libraries like PDF-Lib and jsPDF.
Organizations should implement strict file upload validation, content security policies, and regular security assessments to prevent such vulnerabilities from compromising their password management infrastructure.
#Cyber_Security #Cyber_Security_News #Vulnerability #cyber_security #cyber_security_news #vulnerability
Оригинальная версия на сайте:
Bitwarden PDF File Handler Vulnerability Let Attackers Upload Malicious PDF Files
Author: KaaviyaA critical cross-site scripting (XSS) vulnerability has been discovered in the popular password manager Bitwarden, affecting versions up to 2.25.1.
The security flaw, designated as CVE-2025-5138, resides in the PDF File Handler component and allows attackers to upload malicious PDF files that can execute arbitrary code when viewed by users.
Despite early notification to the vendor, Bitwarden has not responded to the disclosure, leaving millions of users potentially vulnerable to remote attacks.
Bitwarden PDF XSS Vulnerability
The vulnerability stems from insufficient file type restrictions in Bitwarden’s Resources upload feature, which fails to properly validate uploaded PDF documents.
According to security researchers, the flaw is classified under CWE-79 (Cross-site Scripting) and has been assigned a CVSS v3.1 base score of 3.5, indicating moderate severity.
The vulnerability affects an unknown functionality within the PDF File Handler component, where user-controllable input is not properly neutralized before being placed in output that serves web pages to other users.
When attackers exploit this vulnerability, they can manipulate PDF files to inject malicious JavaScript code that executes within the context of the Bitwarden application.
The attack vector requires the attacker to have authenticated access (PR:L – Low Privileges Required) and relies on user interaction (UI:R – User Interaction Required) to trigger the malicious payload.
The vulnerability specifically impacts the integrity of the application (I:L – Low Impact on Integrity) while maintaining no direct effect on confidentiality or availability.
Risk Factors Details Affected ProductsBitwarden versions ≤ 2.25.1 (PDF File Handler component)ImpactAllows execution of arbitrary JavaScript via malicious PDFs, potentially enabling session hijacking, credential theft, or unauthorized actions within the user’s Bitwarden vault.Exploit Prerequisites1. Attacker requires authenticated access (low privileges) 2. User interaction to open malicious PDF 3. Relies on browser PDF rendering enginesCVSS 3.1 Score3.5 (Medium)
Proof of Concept
Security researcher YZS17 has published a detailed proof-of-concept (PoC) demonstrating the exploitation technique on GitHub.
The attack follows a straightforward process: first, an attacker creates a new project within Bitwarden’s interface, then uploads a specially crafted PDF file containing malicious JavaScript code.
When legitimate users subsequently open the PDF file through Google Chrome or other browsers, the embedded code executes automatically.
The PoC reveals that the vulnerability exploits the browser’s native PDF rendering capabilities, bypassing Bitwarden’s security controls.
The malicious PDF file leverages JavaScript injection techniques similar to those documented in portable data exfiltration research, where controlling HTTP hyperlinks within PDF documents can provide access to internal PDF workings.
This technique essentially creates “XSS within the bounds of a PDF document,” allowing attackers to execute arbitrary JavaScript and potentially steal sensitive information from users’ vaults.
Mitigation
Despite researchers contacting Bitwarden early in the disclosure process, the company has failed to acknowledge or respond to the vulnerability report.
This lack of communication raises concerns about Bitwarden’s incident response procedures, particularly given the company’s reputation for robust security practices outlined in their security whitepaper.
Currently, no official patches or countermeasures have been released by Bitwarden. Security experts recommend that organizations using affected versions consider replacing Bitwarden with alternative password management solutions until a fix becomes available.
Users should exercise extreme caution when opening PDF attachments within their Bitwarden vaults and avoid clicking on unknown PDF files shared through the platform.
The vulnerability discovery highlights broader security concerns regarding PDF handling in web applications, as similar injection flaws have been identified in popular PDF libraries like PDF-Lib and jsPDF.
Organizations should implement strict file upload validation, content security policies, and regular security assessments to prevent such vulnerabilities from compromising their password management infrastructure.
#Cyber_Security #Cyber_Security_News #Vulnerability #cyber_security #cyber_security_news #vulnerability
Оригинальная версия на сайте:
