CVE-2026-104063 in Scribus
Summary
by MITRE • 10/30/2026
Scribus before 1.6.7 contains an out-of-bounds read vulnerability in the Mac PICT image loader and import plugin when decoding planar pixel data. Attackers can supply a crafted PICT file with manipulated dimensions that, when placed or imported, causes heap over-reads leading to crashes or heap memory disclosure.
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Analysis
by VulDB Data Team • 10/30/2026
The vulnerability identified in Scribus versions prior to 1.6.7 represents a critical security flaw within the application's image processing subsystem, specifically targeting the Mac PICT format loader and its associated import plugin. This defect arises during the decoding phase of planar pixel data, where the software fails to adequately validate input parameters against allocated memory boundaries. The core technical issue is an out-of-bounds read condition that occurs when the parser processes a maliciously crafted PICT file containing manipulated dimension attributes. By supplying image dimensions that exceed the actual size of the buffer or misrepresenting the layout of planar data, an attacker can force the application to access memory locations outside the intended allocation. This behavior is characteristic of CWE-125, which defines out-of-bounds read vulnerabilities where software reads past the end of a buffer, potentially leading to information disclosure or denial of service conditions depending on how the accessed memory contents are utilized by the subsequent execution flow.
From an operational perspective, this vulnerability poses significant risks to both system stability and data confidentiality. When a user opens or imports a maliciously constructed PICT file, the resulting heap over-read can cause immediate application crashes, leading to a denial of service for legitimate users relying on Scribus for desktop publishing tasks. More critically, if the memory contents read from outside the buffer boundary contain sensitive information such as cryptographic keys, session tokens, or other user data residing in adjacent heap regions, this could lead to unauthorized disclosure of private information. The exploitation vector typically involves social engineering tactics where an attacker distributes a specially crafted file designed to trigger the flaw upon opening within the application environment. This aligns with ATT&CK technique T1203, which covers Exploitation for Client Execution, as the vulnerability relies on user interaction to load the malicious payload into memory and execute the flawed decoding routine.
The impact of this vulnerability extends beyond simple crashes because heap over-reads can sometimes be leveraged in more complex attack chains if combined with other weaknesses or specific runtime conditions. Although primarily classified as an out-of-bounds read, improper handling of such errors can occasionally facilitate further exploitation attempts by leaking memory layout information that aids in bypassing security mitigations like Address Space Layout Randomization. The presence of this flaw indicates a lack of rigorous bounds checking during the parsing of image metadata and pixel data structures. In professional software development for graphic design tools, which often handle untrusted third-party assets, robust input validation is paramount to prevent such memory safety violations.
To mitigate this risk, organizations and individual users must upgrade Scribus to version 1.6.7 or later, where the developers have implemented fixes to properly validate dimension parameters and ensure that all read operations remain within allocated buffer limits. Until an update can be applied, it is advisable to restrict the use of PICT file imports from untrusted sources and consider using alternative image formats with more robust parser implementations if possible. Security teams should also monitor for any indicators of compromise related to unexpected application crashes or memory anomalies in environments where Scribus is deployed as a primary design tool. Regular patch management cycles are essential to address such vulnerabilities promptly, ensuring that the software remains resilient against known exploitation techniques targeting legacy format parsers and memory handling routines.