CVE-2025-61816: Adobe InCopy Buffer Overflow Vulnerability

CVE-2025-61816 Overview

CVE-2025-61816 is a heap-based buffer overflow vulnerability affecting Adobe InCopy versions 20.5, 19.5.5, and earlier. Successful exploitation allows arbitrary code execution in the context of the current user. The flaw requires user interaction: a victim must open a malicious file crafted by the attacker. Adobe disclosed the issue in security bulletin APSB25-107 and the CVE was published to the National Vulnerability Database (NVD) on November 11, 2025. The vulnerability maps to [CWE-122] Heap-based Buffer Overflow and [CWE-787] Out-of-bounds Write.

Critical Impact
Attackers can achieve arbitrary code execution on Windows and macOS systems running vulnerable InCopy versions when a user opens a malicious document.

Affected Products

Adobe InCopy 20.5 and earlier
Adobe InCopy 19.5.5 and earlier
Microsoft Windows and Apple macOS hosts running affected InCopy versions

Discovery Timeline

2025-11-11 - CVE-2025-61816 published to NVD
2025-11-12 - Last updated in NVD database
Vendor advisory - Adobe published Adobe Security Advisory APSB25-107

Technical Details for CVE-2025-61816

Vulnerability Analysis

The vulnerability is a heap-based buffer overflow in Adobe InCopy, a desktop publishing application used for collaborative editorial workflows with Adobe InDesign. When InCopy parses a malformed file, it writes data beyond the bounds of a heap-allocated buffer. The out-of-bounds write corrupts adjacent heap structures, which an attacker can shape to redirect execution flow and run arbitrary code. Code executes with the privileges of the user running InCopy, enabling attackers to read user data, install additional payloads, or pivot deeper into the host environment.

Root Cause

The root cause is improper validation of input data sizes during file parsing, classified as [CWE-122] Heap-based Buffer Overflow with an underlying [CWE-787] Out-of-bounds Write. InCopy allocates a heap buffer based on assumptions that do not hold for attacker-controlled input, and subsequently copies more bytes than the buffer can contain. The overflow overwrites heap metadata or adjacent object fields used later for control-flow decisions.

Attack Vector

Exploitation requires local user interaction. The attacker delivers a crafted InCopy document through email, file shares, removable media, or web download. When the victim opens the file in a vulnerable version of InCopy, the parsing routine triggers the overflow. There is no network attack surface, and authentication is not required for the attacker. The vulnerability does not appear in the CISA Known Exploited Vulnerabilities catalog, and no public proof-of-concept is currently listed.

No verified public exploit code is available. See the Adobe Security Advisory APSB25-107 for vendor technical details.

Detection Methods for CVE-2025-61816

Indicators of Compromise

Unexpected child processes spawned by InCopy.exe on Windows or Adobe InCopy on macOS, particularly shells, scripting engines, or rundll32.exe
InCopy process crashes with heap corruption signatures in Windows Error Reporting or macOS crash logs shortly after opening a document
Outbound network connections originating from the InCopy process to untrusted hosts following document open
New persistence artifacts (scheduled tasks, LaunchAgents, registry Run keys) created in the user context after InCopy activity

Detection Strategies

Monitor process lineage for InCopy spawning interpreters such as powershell.exe, cmd.exe, wscript.exe, bash, or osascript
Alert on file writes by InCopy to autorun and startup locations in the user profile
Inspect email gateways and web proxies for InCopy file types (.icml, .indd, .incx) originating from untrusted senders
Correlate InCopy crash telemetry with subsequent suspicious user-context activity within a short time window

Monitoring Recommendations

Enable EDR rules that flag exploitation behaviors from productivity applications, including memory protection violations
Forward Adobe application logs and OS-level process telemetry to a central SIEM or data lake for retention and correlation
Track endpoint inventory of installed InCopy versions to identify hosts still running 20.5, 19.5.5, or earlier

How to Mitigate CVE-2025-61816

Immediate Actions Required

Upgrade Adobe InCopy to the fixed versions listed in Adobe Security Advisory APSB25-107
Identify all hosts running InCopy 20.5, 19.5.5, or earlier and prioritize patching on systems handling externally sourced documents
Instruct users not to open InCopy files received from untrusted or unexpected sources until patching is complete

Patch Information

Adobe released updated InCopy builds addressing CVE-2025-61816 as part of bulletin APSB25-107. Administrators should deploy the vendor-provided update through Adobe Creative Cloud or managed software distribution tooling. Confirm the installed version matches or exceeds the fixed release published in the advisory.

Workarounds

Restrict opening of InCopy documents to files originating from trusted internal sources until patches are applied
Apply application allowlisting and attachment filtering to block InCopy file types from untrusted email senders
Run InCopy under a least-privilege user account to limit the impact of successful code execution
Enable operating system exploit mitigations such as Windows Defender Exploit Guard and macOS Hardened Runtime where supported