CVE-2026-27303: Adobe Connect RCE Vulnerability

CVE-2026-27303 Overview

Adobe Connect versions 2025.3, 12.10 and earlier are affected by a Deserialization of Untrusted Data vulnerability (CWE-502) that could result in arbitrary code execution in the context of the current user. This critical insecure deserialization flaw allows remote attackers to execute arbitrary code without requiring user interaction. The vulnerability has a changed scope, meaning successful exploitation can impact resources beyond the vulnerable component's security scope.

Critical Impact

Remote attackers can achieve arbitrary code execution through deserialization of untrusted data, potentially compromising enterprise web conferencing infrastructure and sensitive meeting data.

Affected Products

• Adobe Connect version 2025.3 and earlier
• Adobe Connect version 12.10 and earlier
• All prior Adobe Connect releases with the vulnerable deserialization component

Discovery Timeline

• 2026-04-14 - CVE-2026-27303 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2026-27303

Vulnerability Analysis

This vulnerability stems from improper handling of serialized data within Adobe Connect's processing pipeline. When the application deserializes untrusted data without adequate validation, it allows attackers to inject malicious serialized objects that execute arbitrary code upon deserialization. The changed scope indicator means that a successful exploit can affect components beyond Adobe Connect itself, potentially impacting the underlying server infrastructure or other connected systems.

The deserialization vulnerability is particularly dangerous in enterprise environments where Adobe Connect is used for web conferencing, as successful exploitation could lead to complete system compromise, data exfiltration, or lateral movement within corporate networks.

Root Cause

The root cause is classified under CWE-502 (Deserialization of Untrusted Data). Adobe Connect fails to properly validate or sanitize serialized input before deserializing it, allowing attackers to craft malicious payloads that execute arbitrary code when processed by the application. This class of vulnerability typically occurs when applications blindly trust serialized data from untrusted sources without implementing proper type checking, integrity verification, or sandboxing mechanisms.

Attack Vector

The attack vector is network-based, allowing remote exploitation without requiring authentication. Attackers can craft specially formatted serialized payloads and submit them to vulnerable Adobe Connect endpoints. The vulnerability does not require user interaction, meaning attackers can exploit it autonomously once they identify a vulnerable target. The changed scope allows the attacker to pivot from the Adobe Connect context to affect other system components, significantly amplifying the potential damage.

Exploitation typically involves identifying deserialization endpoints, crafting gadget chains compatible with the application's classpath, and delivering the malicious payload through HTTP requests to the vulnerable Adobe Connect server.

Detection Methods for CVE-2026-27303

Indicators of Compromise

• Unusual serialized object payloads in HTTP request bodies targeting Adobe Connect endpoints
• Unexpected process spawning or command execution originating from Adobe Connect server processes
• Anomalous network connections initiated by the Adobe Connect application server
• Log entries showing deserialization errors or exceptions with suspicious class names

Detection Strategies

• Monitor Adobe Connect server logs for deserialization exceptions or errors involving unexpected class types
• Deploy network intrusion detection signatures to identify known Java/serialization exploit patterns
• Implement web application firewall rules to inspect and block suspicious serialized data in requests
• Enable endpoint detection and response (EDR) monitoring on Adobe Connect servers for anomalous process behavior

Monitoring Recommendations

• Configure alerting for unusual outbound network connections from Adobe Connect servers
• Monitor for unexpected child processes spawned by the Adobe Connect application
• Track file system modifications in Adobe Connect installation directories
• Review authentication logs for any anomalous access patterns post-exploitation

How to Mitigate CVE-2026-27303

Immediate Actions Required

• Apply the security patch from Adobe immediately by referencing Adobe Security Advisory APSB26-37
• Restrict network access to Adobe Connect servers to trusted IP ranges where possible
• Enable enhanced logging and monitoring on Adobe Connect infrastructure
• Review and audit any Adobe Connect servers for signs of compromise

Patch Information

Adobe has released a security update addressing this vulnerability. Administrators should consult the Adobe Security Advisory APSB26-37 for detailed patch information and upgrade instructions. Organizations should prioritize patching Adobe Connect installations to versions newer than 2025.3 and 12.10 to remediate this critical vulnerability.

Workarounds

• Implement network segmentation to isolate Adobe Connect servers from critical infrastructure
• Deploy a web application firewall with deserialization attack signatures enabled
• Restrict access to Adobe Connect administrative interfaces to trusted networks only
• Consider temporarily disabling Adobe Connect services until patches can be applied in high-risk environments
• Monitor Adobe Connect server processes for suspicious activity using endpoint protection solutions

For organizations unable to patch immediately, implementing strict network controls and enhanced monitoring provides defense-in-depth until the security update can be applied.