CVE-2026-34695: Adobe InDesign Buffer Overflow Vulnerability

CVE-2026-34695 Overview

CVE-2026-34695 is a stack-based buffer overflow vulnerability in Adobe InDesign Desktop. The flaw affects InDesign Desktop versions 21.3, 20.5.3, and earlier on both Windows and macOS. Successful exploitation allows arbitrary code execution in the context of the user running the application. The vulnerability is tracked under [CWE-121] (Stack-based Buffer Overflow) and requires user interaction, as a victim must open a crafted InDesign file. Adobe published security advisory APSB26-58 to address the issue.

Critical Impact

Attackers can achieve arbitrary code execution under the current user's privileges by convincing a victim to open a malicious InDesign document.

Affected Products

• Adobe InDesign Desktop version 21.3 and earlier 21.x releases
• Adobe InDesign Desktop version 20.5.3 and earlier 20.x releases
• Microsoft Windows and Apple macOS installations of the affected versions

Discovery Timeline

• 2026-06-09 - CVE-2026-34695 published to NVD
• 2026-06-10 - Last updated in NVD database

Technical Details for CVE-2026-34695

Vulnerability Analysis

The vulnerability is a stack-based buffer overflow within Adobe InDesign Desktop's file parsing logic. Adobe InDesign processes complex document formats containing embedded structures, fonts, and graphics resources. When the application parses a malformed input field, it writes beyond the bounds of a fixed-size stack buffer. The overflow corrupts adjacent stack memory, including saved return addresses and local variables. Exploitation results in arbitrary code execution with the privileges of the current user. The attack vector is local because the malicious file must reach the victim's system, but delivery commonly occurs through email attachments, shared drives, or download links.

Root Cause

The root cause is missing or insufficient bounds checking when InDesign reads attacker-controlled length fields from a document. The parser copies data into a stack-allocated buffer without validating that the source size fits the destination. This pattern aligns with [CWE-121] and is typical of legacy file format parsers that predate modern safe-string APIs.

Attack Vector

Exploitation requires user interaction. An attacker crafts a malicious .indd or related InDesign file, then delivers it via phishing, watering-hole sites, or document sharing platforms. When the victim opens the file in a vulnerable version of InDesign, the overflow triggers and the attacker's payload executes in the user's security context. No authentication or elevated privileges are required from the attacker.

No public proof-of-concept exploit code is available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.

Detection Methods for CVE-2026-34695

Indicators of Compromise

• Unexpected child processes spawned by InDesign.exe on Windows or Adobe InDesign on macOS, such as cmd.exe, powershell.exe, or shell interpreters
• InDesign process crashes followed by suspicious file or registry writes shortly after opening a document
• Inbound .indd, .indt, .idml, or related InDesign files from untrusted senders or external file shares

Detection Strategies

• Monitor endpoint telemetry for anomalous process lineage where InDesign launches scripting or LOLBin processes
• Flag InDesign crash events combined with new persistence artifacts in user-writable locations such as %AppData% or ~/Library/LaunchAgents
• Inspect email and web gateway logs for InDesign document attachments delivered from external or low-reputation sources

Monitoring Recommendations

• Track InDesign version inventory across Windows and macOS endpoints to identify hosts still running 21.3, 20.5.3, or earlier
• Alert on outbound network connections initiated by InDesign.exe to non-Adobe destinations following document open events
• Correlate file open events for InDesign documents with subsequent EDR detections within a short time window

How to Mitigate CVE-2026-34695

Immediate Actions Required

• Update Adobe InDesign Desktop to the fixed versions published in Adobe Security Advisory APSB26-58
• Restrict opening InDesign files received from external or untrusted sources until patching is verified
• Apply application allow-listing and least-privilege policies so that compromise of InDesign cannot escalate beyond the user account

Patch Information

Adobe released fixed builds of InDesign Desktop that resolve the stack-based buffer overflow. Administrators should consult Adobe Security Advisory APSB26-58 for the exact patched version numbers for the 21.x and 20.x branches and deploy updates through Adobe Creative Cloud or enterprise deployment tooling.

Workarounds

• Block delivery of InDesign file types at email and web gateways for users who do not require them
• Train users to avoid opening unsolicited design files and to validate the sender before opening attachments
• Run InDesign under a standard user account, never with administrative privileges, to limit the blast radius of exploitation

# Example: enumerate installed InDesign versions on Windows endpoints via PowerShell
Get-ItemProperty 'HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\*' |
  Where-Object { $_.DisplayName -like 'Adobe InDesign*' } |
  Select-Object DisplayName, DisplayVersion, InstallLocation