CVE-2006-0528 in Evolution
Summary
by MITRE
The cairo library (libcairo), as used in GNOME Evolution and possibly other products, allows remote attackers to cause a denial of service (persistent client crash) via an attached text file that contains "Content-Disposition: inline" in the header, and a very long line in the body, which causes the client to repeatedly crash until the e-mail message is manually removed, possibly due to a buffer overflow, as demonstrated using an XML attachment.
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Analysis
by VulDB Data Team • 01/19/2025
The cairo graphics library vulnerability identified as CVE-2006-0528 represents a significant denial of service flaw that affects email clients processing text attachments. This vulnerability specifically impacts the GNOME Evolution email client and potentially other applications utilizing the cairo graphics library for rendering text content. The flaw manifests when processing email messages containing specially crafted text files with specific header and body characteristics that trigger repeated client crashes.
The technical mechanism behind this vulnerability involves the cairo library's handling of text rendering when encountering email attachments with "Content-Disposition: inline" headers combined with excessively long lines in the message body. This particular combination causes the library to process malformed input in a way that leads to persistent client instability. The vulnerability demonstrates characteristics consistent with buffer overflow conditions where the library fails to properly validate input length limits during text processing operations, leading to memory corruption that results in application crashes.
The operational impact of this vulnerability extends beyond simple service disruption, as it creates a persistent denial of service condition that requires manual intervention to resolve. Email clients affected by this vulnerability will repeatedly crash when attempting to render the maliciously crafted email messages, forcing users to manually delete the problematic messages to restore normal functionality. This creates significant operational overhead for end users and system administrators who must identify and remove the malicious attachments from their email inboxes.
This vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and demonstrates how improper input validation can lead to denial of service scenarios in graphics rendering libraries. The ATT&CK framework categorizes this as a privilege escalation technique through application-level exploitation, where attackers can leverage this vulnerability to disrupt normal email operations. The vulnerability's exploitation requires minimal technical expertise to demonstrate, making it particularly dangerous in environments where users may inadvertently open malicious email attachments.
The recommended mitigations for this vulnerability include applying the vendor-provided patches to the cairo library and updating affected email clients to versions that properly handle input validation for text rendering operations. System administrators should implement email filtering rules to block attachments with suspicious Content-Disposition headers and excessively long lines. Additionally, users should exercise caution when opening email attachments, particularly those with XML or text file extensions, and should avoid automatic rendering of potentially malicious content. Regular security updates and vulnerability assessments should be implemented to prevent similar issues in other graphics libraries and email processing components that may exhibit similar buffer handling vulnerabilities.