InDesign - CraftedSignal Threat Feed

Adobe InDesign Heap-Based Buffer Overflow Vulnerability (CVE-2026-27238)

hello@craftedsignal.io — Tue, 23 Jan 2024 12:00:00 +0000

CVE-2026-27238 describes a heap-based buffer overflow vulnerability affecting Adobe InDesign Desktop versions 20.5.2, 21.2, and earlier. The vulnerability could allow an attacker to execute arbitrary code within the security context of the currently logged-in user. Successful exploitation of this vulnerability requires a user to open a specially crafted, malicious InDesign file. This vulnerability was reported on April 14, 2026, and the primary concern for defenders lies in preventing users from interacting with potentially malicious InDesign files delivered via phishing or other means. Defenders should ensure users are educated about the risks of opening untrusted files and that InDesign installations are up to date.

Attack Chain

Delivery: The attacker crafts a malicious InDesign file designed to trigger the heap-based buffer overflow. The file is delivered to the victim via email, shared network drive, or other file-sharing mechanisms.
User Interaction: The victim, unaware of the file's malicious nature, opens the crafted InDesign file using a vulnerable version of Adobe InDesign.
Exploitation: Upon opening the malicious file, the heap-based buffer overflow is triggered due to the way InDesign parses the file's data structures.
Code Execution: The buffer overflow allows the attacker to overwrite parts of InDesign's memory, injecting and executing arbitrary code.
Privilege Context: The injected code executes within the context of the current user account, inheriting its privileges and access rights.
Persistence/Lateral Movement (Optional): Depending on the attacker's objectives, they may attempt to establish persistence on the system (e.g., via registry keys or scheduled tasks) or use the compromised system as a pivot point for lateral movement within the network.
Objective Achieved: The attacker achieves their objective, which may include data theft, installation of malware, or further compromise of the system or network.

Impact

Successful exploitation of CVE-2026-27238 can lead to arbitrary code execution on the victim's machine. The impact includes potential data loss, system compromise, and further propagation of malware within an organization. Given the widespread use of Adobe InDesign in creative and publishing industries, a successful campaign could affect a significant number of users and organizations. The severity is compounded by the ease with which malicious files can be disseminated.

Recommendation

Educate users about the dangers of opening unsolicited or untrusted files, particularly those with the .indd extension associated with Adobe InDesign.
Deploy the Sigma rule Detect Suspicious InDesign Child Processes to identify potentially malicious processes spawned by InDesign.
Monitor process creation events for unusual child processes of InDesign, as highlighted in the Sigma rule Detect Suspicious InDesign Child Processes.
Update Adobe InDesign to the latest version to patch CVE-2026-27238 and other security vulnerabilities.

Adobe InDesign Use-After-Free Vulnerability (CVE-2026-27283)

hello@craftedsignal.io — Wed, 03 Jan 2024 12:00:00 +0000

CVE-2026-27283 is a use-after-free vulnerability affecting Adobe InDesign Desktop versions 20.5.2, 21.2, and earlier. This vulnerability can be exploited when a user opens a malicious InDesign file. Successful exploitation could lead to arbitrary code execution within the context of the current user. The vulnerability was reported to Adobe and assigned a CVSS v3.1 base score of 7.8, indicating a high severity. This vulnerability requires user interaction. The report highlights that a victim must open a malicious file for the exploitation to occur. Organizations utilizing vulnerable versions of InDesign should take appropriate actions to mitigate this risk.

Attack Chain

Attacker crafts a malicious Adobe InDesign file designed to trigger the use-after-free vulnerability.
The attacker delivers the malicious InDesign file to the victim via email or other file-sharing methods.
The victim, unaware of the malicious nature, opens the crafted InDesign file using a vulnerable version of Adobe InDesign Desktop (20.5.2, 21.2, or earlier).
InDesign attempts to access a memory location that has already been freed, triggering the use-after-free condition.
The attacker gains control of the program counter due to the memory corruption.
The attacker injects and executes arbitrary code within the context of the InDesign process.
The attacker escalates privileges or performs malicious actions such as installing malware, stealing data, or compromising the system.

Impact

Successful exploitation of CVE-2026-27283 allows for arbitrary code execution within the context of the user running Adobe InDesign. This could allow an attacker to install programs, view, change, or delete data, or create new accounts with full user rights. The vulnerability affects Adobe InDesign Desktop users, potentially impacting creative professionals and organizations that rely on InDesign for their workflows. The vulnerability requires user interaction to trigger.

Recommendation

Deploy the Sigma rule "Detect InDesign Suspicious File Opens" to identify potential attempts to exploit CVE-2026-27283 by monitoring process creation events related to InDesign opening files (see rules).
Educate users about the risks of opening files from untrusted sources and the importance of verifying the legitimacy of InDesign files before opening them.
Monitor file creation events for InDesign processes creating suspicious files (see rules).
Refer to Adobe's security bulletin APSB26-32 for official guidance and updates regarding CVE-2026-27283 (references).

Adobe InDesign Out-of-Bounds Write Vulnerability (CVE-2026-27291)

hello@craftedsignal.io — Tue, 02 Jan 2024 10:00:00 +0000

CVE-2026-27291 affects Adobe InDesign Desktop versions 20.5.2, 21.2, and earlier. This out-of-bounds write vulnerability can be exploited if a user opens a specially crafted, malicious file. Successful exploitation allows an attacker to execute arbitrary code within the security context of the current user. The attacker needs to convince the user to open the malicious file, indicating a social engineering aspect to the attack. This vulnerability poses a significant risk to organizations that rely on Adobe InDesign for creative work, as it could lead to system compromise and data breaches if exploited.

Attack Chain

An attacker crafts a malicious Adobe InDesign file.
The attacker delivers the malicious file to a target user, possibly via email or other file-sharing methods.
The user, unaware of the file's malicious nature, opens it in a vulnerable version of Adobe InDesign (20.5.2, 21.2 or earlier).
InDesign attempts to process the file, triggering the out-of-bounds write vulnerability.
The out-of-bounds write leads to memory corruption.
The attacker leverages the memory corruption to inject and execute arbitrary code.
The attacker gains control of the InDesign process, inheriting the user's privileges.
The attacker can now perform malicious actions, such as installing malware, stealing data, or moving laterally within the network.

Impact

Successful exploitation of CVE-2026-27291 can lead to arbitrary code execution on the targeted system, effectively allowing an attacker to take control of the application and potentially the entire machine. This could result in data theft, malware installation, or further network compromise. The vulnerability impacts all users of affected Adobe InDesign versions. While the number of affected users is not specified, the potential impact is widespread among creative professionals and organizations that rely on InDesign.

Recommendation

Upgrade Adobe InDesign to a version beyond 21.2 to patch CVE-2026-27291 as indicated in Adobe's security advisory (https://helpx.adobe.com/security/products/indesign/apsb26-32.html).
Deploy the provided Sigma rule to detect suspicious process creation events following the launch of InDesign to identify potential exploitation attempts.
Educate users about the risks of opening files from untrusted sources to mitigate the initial access vector.