CVE-2026-48294: Adobe Acrobat XSS Vulnerability

CVE-2026-48294 Overview

CVE-2026-48294 is a Universal Cross-Site Scripting (UXSS) class vulnerability in the Adobe Acrobat PDF Extension for Google Chrome. Versions 26.5.2.2 and earlier are affected. An attacker can leverage the flaw to bypass the browser's same-origin policy and read data tied to the victim's session across origins. Exploitation requires user interaction. The victim must visit a maliciously crafted URL or interact with a compromised web page that triggers the extension's vulnerable code path. The scope is changed, meaning the impact extends beyond the vulnerable component to other browser origins. The vulnerability is classified under [CWE-79] (Improper Neutralization of Input During Web Page Generation).

Critical Impact
Successful exploitation grants an attacker cross-origin read access to session-bound data, including authenticated content from third-party web applications loaded in the victim's browser.

Affected Products

Adobe Acrobat PDF Extension for Chrome, version 26.5.2.2
All prior Adobe Acrobat PDF Extension (Chrome) releases
Browsers with the vulnerable extension installed and active

Discovery Timeline

2026-06-17 - CVE-2026-48294 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2026-48294

Vulnerability Analysis

The vulnerability is a Universal Cross-Site Scripting flaw in a browser extension. Unlike traditional XSS, UXSS abuses the extension's elevated browser privileges to inject script execution into arbitrary origins. Because browser extensions can interact with any page the user visits, a flaw in input handling allows attacker-controlled content to execute in the security context of unrelated sites. The CVSS scope change reflects this behavior. Code running inside the extension's vulnerable handler escapes into web origins it would not normally affect. An attacker can therefore read cookies, session tokens, DOM contents, and authenticated responses from sites the victim is logged into.

Root Cause

The defect stems from improper neutralization of input rendered by the extension into a web page context [CWE-79]. The extension processes attacker-influenced data without sufficient sanitization or contextual encoding before injecting it into a DOM that inherits cross-origin privileges. Adobe has not published the affected component internals, but the UXSS classification confirms the boundary violation occurs between extension-controlled content and host page origins.

Attack Vector

Exploitation is network-based and requires user interaction. The attacker hosts a crafted URL or compromises a legitimate page. When the victim, who has the Adobe Acrobat PDF Extension installed, loads the page, the extension processes the malicious payload and executes attacker script in a privileged context. The attacker can then exfiltrate session data, perform actions on behalf of the user, or pivot to additional cross-origin reads. No authentication is required to deliver the payload.

No verified public proof-of-concept is available. See the Chrome Web Store Listing for the affected extension distribution.

Detection Methods for CVE-2026-48294

Indicators of Compromise

Browser telemetry showing the Adobe Acrobat PDF Extension at version 26.5.2.2 or earlier on managed endpoints
Outbound HTTP requests from browser processes to unfamiliar domains immediately after PDF link interactions
Unexpected cross-origin fetch or XMLHttpRequest activity correlated with extension execution
Anomalous session token reuse from geographic locations inconsistent with the user's baseline

Detection Strategies

Inventory installed Chrome extensions across the fleet and flag Adobe Acrobat PDF Extension versions at or below 26.5.2.2
Monitor browser extension update channels and Chrome Web Store telemetry for version drift
Correlate web proxy logs with endpoint browser activity to identify visits to suspected exploit pages
Hunt for session anomalies in identity provider logs that follow user interaction with PDF-related URLs

Monitoring Recommendations

Ingest Chrome enterprise policy and extension inventory data into your SIEM for continuous version tracking
Alert on browser child processes spawning unexpected network connections following extension activation
Track authentication events for high-value SaaS applications and review for cross-origin session reuse

How to Mitigate CVE-2026-48294

Immediate Actions Required

Update the Adobe Acrobat PDF Extension to the version released after 26.5.2.2 through the Chrome Web Store
Force extension updates via Chrome enterprise policy rather than relying on user-initiated upgrades
Audit all managed browsers and remove the extension where it is not business-critical
Notify users to avoid clicking untrusted PDF links until patching is verified

Patch Information

Adobe distributes the fix through the Chrome Web Store. Administrators should confirm the deployed version is later than 26.5.2.2 on every endpoint. Refer to the Chrome Web Store Listing for the current published build. No vendor advisory URL was included in the NVD record at the time of publication.

Workarounds

Disable or remove the Adobe Acrobat PDF Extension via Chrome enterprise policy until patched builds are confirmed deployed
Block extension installation through ExtensionInstallBlocklist and allowlist only vetted versions
Restrict the extension's host permissions to a minimal set of trusted domains where feasible
Enforce session cookie attributes such as SameSite=Strict and short token lifetimes on internal applications to reduce UXSS impact

bash

# Chrome enterprise policy example to block the vulnerable extension by ID
# Place under: /etc/opt/chrome/policies/managed/adobe-acrobat-block.json
{
  "ExtensionInstallBlocklist": [
    "efaidnbmnnnibpcajpcglclefindmkaj"
  ],
  "ExtensionInstallForcelist": [],
  "ExtensionSettings": {
    "efaidnbmnnnibpcajpcglclefindmkaj": {
      "installation_mode": "blocked",
      "blocked_install_message": "Adobe Acrobat PDF Extension is blocked pending CVE-2026-48294 remediation."
    }
  }
}