CVE-2026-48294: Adobe Acrobat Chrome Extension UXSS Session Data Disclosure

Technical summary

CVE-2026-48294 is a universal XSS (UXSS) vulnerability in the Adobe Acrobat PDF Extension for Chrome that enables cross-origin data disclosure. The vulnerability stems from improper handling of same-origin policy enforcement, allowing script execution within privileged extension contexts to access data across security boundaries. The CVSS 3.1 vector (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N) reflects network exploitability with low complexity, user interaction requirement, scope change, and confidentiality impact. This is mapped to CWE-79 (improper neutralization of input during web page generation). The scope change parameter indicates the vulnerability can affect resources beyond the vulnerable component itself.

Business impact

Session hijacking via this vulnerability could expose user authentication tokens, browsing history, and sensitive document metadata accessed through the Acrobat extension. For organizations where users routinely open PDFs from external sources or email, the risk of data exfiltration is elevated. Attackers could craft phishing emails or malicious websites that exploit this flaw to harvest session credentials without triggering obvious security warnings, potentially compromising both personal and corporate data handling.

Affected systems

Adobe Acrobat PDF Extension for Chrome in versions 26.5.2.2 and earlier are affected. Users running these versions on any operating system supported by Chrome (Windows, macOS, Linux) face exploitation risk. The vulnerability does not affect standalone Adobe Acrobat Reader or other browsers' PDF handlers unless they use the same underlying vulnerable extension code.

Exploitability

Exploitation is practical but requires user interaction—a victim must be directed to a malicious URL or compromised webpage. The attack complexity is low, meaning a standard attacker with network access can craft the exploit without specialized resources or privileged system access. No authentication is required. The active exploitation likelihood is moderate; while the technique requires social engineering, UXSS vulnerabilities are well-understood in the security community and proof-of-concept development is straightforward.

Remediation

Users should update the Adobe Acrobat PDF Extension for Chrome to a version later than 26.5.2.2. Adobe typically delivers updates through the Chrome Web Store automatically; users can manually verify the extension version in Chrome's extension settings. Organizations should enforce extension update policies and consider disabling the extension if an immediate update is not feasible. Where feasible, use alternative PDF viewers or restrict PDF opening to trusted sources.

Patch guidance

Verify that the Adobe Acrobat PDF Extension for Chrome is updated to the latest available version beyond 26.5.2.2 by checking chrome://extensions in your browser and confirming the extension version number. If automatic updates are disabled, manually update by visiting the Chrome Web Store page for the extension or ensure auto-update is enabled in browser settings. Test the patched version with internal PDF workflows to ensure no compatibility issues. Document the patch date for compliance records.

Detection guidance

Monitor Chrome extension permissions and versions in your environment using endpoint management tools. Detect anomalous script execution within the Acrobat extension context using browser security monitoring or EDR solutions capable of browser process inspection. Hunt for suspicious cross-origin requests originating from PDF-viewing sessions. Review web proxy logs for attempts to access URLs hosting UXSS payloads. Educate users to avoid clicking untrusted PDF links and to verify sender authenticity before opening attachments.

Why prioritize this

This vulnerability merits urgent attention despite not being on the KEV catalog. The combination of high CVSS score (7.4), practical user-interaction-based exploitation, scope change enabling cross-origin attacks, and the prevalence of Chrome browser usage in enterprise environments creates significant organizational risk. Session data disclosure can cascade into lateral movement or credential theft. The low barrier to exploitation (no special tools required) means threat actors will likely develop functional exploits quickly.

Risk score, explained

The CVSS 7.4 HIGH rating reflects: (1) network-reachable attack surface with no privilege requirements; (2) low attack complexity allowing easy exploitation; (3) user interaction as a practical but single point of friction; (4) scope change indicating the vulnerability compromises security mechanisms beyond the vulnerable component; (5) high confidentiality impact through session and data disclosure. The score does not factor ransomware activity or active exploitation in the wild, which would further elevate real-world risk for organizations.

Frequently asked questions