Executive Summary

CVE-2026-54231 is a content injection vulnerability in the ABRT (Automatic Bug Reporting Tool) post-create event handler scripts. The vulnerability arises because the event script queries the systemd journal for log entries related to a crashed process and writes those results to files in the dump directory without sanitizing embedded control characters.

A local user can exploit this by injecting newline characters into syslog messages, which allows them to control the content that root writes to files in the dump directory. This is done by pre-populating the systemd journal with specially crafted entries where the process name matches common names, enabling arbitrary content injection into the journal output.

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Impact Analysis

This vulnerability allows a local attacker to inject arbitrary content into files that are written by root in the dump directory. This can lead to unauthorized modifications or the creation of malicious files.

Such unauthorized file modifications could potentially be used to mislead administrators, hide malicious activity, or corrupt debugging information, impacting system integrity and trustworthiness.

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Detection Guidance

This vulnerability can be detected by examining the systemd journal for suspicious log entries where newline characters or other control characters have been embedded in syslog messages by local users. Since the vulnerability involves injection of arbitrary content into the journal output, checking for unusual or multiline syslog entries associated with common process names is key.

A practical approach is to use the journalctl command to query the journal for entries with _COMM matching common process names (e.g., "sleep") and inspect the output for unexpected newline characters or injected content.

• journalctl _COMM=sleep
• journalctl _COMM=<process_name> | grep -P '\n'

Additionally, monitoring the dump directory files (such as var_log_messages) created by ABRT for unexpected or suspicious content can help detect exploitation attempts.

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Mitigation Strategies

Immediate mitigation steps include restricting local user permissions to prevent unauthorized writing of syslog messages with embedded control characters.

Since the vulnerability arises from unsanitized content being written by root to dump directory files, limiting local user ability to inject malicious syslog entries reduces risk.

Additionally, monitoring and cleaning the systemd journal for suspicious entries and applying any available patches or updates to ABRT that address this issue are recommended.

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Compliance Impact

The vulnerability allows a local attacker to inject arbitrary content into files written by root in the dump directory, potentially leading to unauthorized modifications or malicious file creation.

Such unauthorized modifications could impact the integrity and reliability of system logs and reports, which are often critical for compliance with standards like GDPR and HIPAA that require accurate and tamper-proof audit trails.

However, the provided information does not explicitly describe direct effects on compliance with these regulations.

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