CVE-2018-21262 in Mattermost Server
Summary
by MITRE
An issue was discovered in Mattermost Server before 4.7.3. It allows attackers to cause a denial of service (application crash) via invalid LaTeX text.
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Analysis
by VulDB Data Team • 10/25/2020
The vulnerability identified as CVE-2018-21262 represents a critical denial of service flaw within the Mattermost Server platform prior to version 4.7.3. This issue specifically targets the server's handling of LaTeX text processing, creating a scenario where maliciously crafted LaTeX content can trigger application instability and eventual system crash. The vulnerability exists in the server's text rendering engine which processes mathematical notation and scientific formulas through LaTeX markup, making it particularly dangerous in collaborative environments where users frequently share complex technical content.
The technical flaw stems from insufficient input validation and sanitization within the LaTeX processing module of Mattermost Server. When the system encounters malformed or improperly structured LaTeX text, the rendering engine fails to properly handle the error conditions, leading to uncontrolled application termination. This represents a classic buffer overflow or exception handling vulnerability where the system does not gracefully manage malformed input data. The issue falls under CWE-20, which categorizes improper input validation as a fundamental weakness in software security design. Attackers can exploit this by crafting specific LaTeX sequences that cause the server to enter an unrecoverable state during processing, effectively disabling the service for legitimate users.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the entire communication platform. In enterprise environments where Mattermost serves as a primary collaboration tool, a successful attack could result in complete service outages affecting thousands of users across multiple channels and teams. The vulnerability is particularly concerning because it requires minimal technical expertise to exploit, making it accessible to attackers with basic knowledge of LaTeX syntax. This creates a significant risk for organizations relying on Mattermost for critical business communications, as the denial of service can occur without any authentication requirements and can be triggered through simple message posting operations.
Organizations affected by CVE-2018-21262 should prioritize immediate patching to version 4.7.3 or later, which includes proper input validation and error handling for LaTeX processing. Additional mitigations should include implementing content filtering at network boundaries to block suspicious LaTeX sequences, establishing monitoring for unusual application crash patterns, and conducting security assessments of all text processing components. The vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through application-level vulnerabilities. Administrators should also consider implementing rate limiting and input sanitization measures to reduce the attack surface and prevent exploitation through automated means. Regular security updates and vulnerability assessments are essential to maintain protection against similar flaws in text rendering and processing components.