CVE-2026-21321: 
Adobe After Effects vulnerability analysis and mitigation

CVE-2026-21321 is an Integer Overflow or Wraparound vulnerability in Adobe After Effects that could result in arbitrary code execution in the context of the current user. It affects Adobe After Effects versions 25.6 and earlier (all versions prior to 25.6.4). Adobe disclosed and patched this vulnerability on February 10, 2026. It carries a CVSS v3.1 base score of 7.8 (High) (Adobe Advisory).

The vulnerability is classified as CWE-190 (Integer Overflow or Wraparound), where improper handling of arithmetic operations on integer values can cause the value to wrap around, leading to memory corruption or unexpected behavior that an attacker can leverage for arbitrary code execution. Exploitation requires a local attack vector — specifically, a victim must be socially engineered into opening a specially crafted malicious file within After Effects. No authentication or elevated privileges are required on the part of the attacker; only user interaction is needed. This maps to CAPEC-92 (Forced Integer Overflow) as the attack pattern (Adobe Advisory).

Successful exploitation allows an attacker to execute arbitrary code with the privileges of the currently logged-in user running Adobe After Effects, resulting in high confidentiality, integrity, and availability impact. An attacker could read sensitive files, modify or delete data, or cause the application to crash. Since execution occurs in the user's context, the impact is scoped to the affected user account, though it could serve as a foothold for further lateral movement depending on the user's permissions (Adobe Advisory).

1. Craft malicious file: An attacker creates a specially crafted After Effects project file (or supported media file) that triggers an integer overflow condition when parsed by the application.
2. Social engineering delivery: The attacker delivers the malicious file to the target via email attachment, file-sharing platform, or a compromised website, convincing the victim to open it.
3. Victim opens file: The victim opens the malicious file in Adobe After Effects version 25.6 or earlier.
4. Integer overflow triggered: During file parsing, an arithmetic operation on an integer value overflows or wraps around, corrupting adjacent memory.
5. Arbitrary code execution: The memory corruption is leveraged to redirect execution flow, allowing the attacker to execute arbitrary code with the privileges of the current user (Adobe Advisory).

• Process: Unexpected child processes spawned by Adobe After Effects (e.g., cmd.exe, powershell.exe, bash, curl, or other shells/utilities) that are not typical for normal application operation.
• File System: Unusual files written to the user's temp directory or After Effects working directories shortly after opening an untrusted project file; unexpected executables or scripts created in user-writable locations.
• Network: Outbound network connections initiated by the After Effects process to unknown or suspicious external IP addresses or domains.
• Logs: Application crash logs or Windows Event Logs indicating memory access violations or abnormal termination of After Effects around the time a file was opened.

Adobe has released a patch in After Effects version 25.6.4, which resolves this vulnerability. Users should update to version 25.6.4 or later immediately via the Creative Cloud desktop application. As an interim workaround, organizations should restrict user access to After Effects, educate users to avoid opening After Effects project files from untrusted or unknown sources, and consider disabling After Effects in environments where it is not actively required (Adobe Advisory).

The CIS (Center for Internet Security) issued an advisory noting that multiple vulnerabilities in Adobe products, including this one, could allow for arbitrary code execution, recommending prompt patching (CIS Advisory). Tenable published detection plugins for this vulnerability. General community reaction has been muted given the lack of public exploit code and no observed in-the-wild exploitation.