CVE-2026-54231: libreport Information Disclosure Flaw

CVE-2026-54231 Overview

CVE-2026-54231 is a content injection vulnerability in the Automatic Bug Reporting Tool (ABRT) post-create event handler scripts shipped with libreport. The post-create event script queries the systemd journal for log entries matching the crashed process and writes those results to files inside the crash dump directory. The script does not sanitize embedded control characters in journal output. A local authenticated user can inject newline characters into syslog messages and control content that the root user subsequently writes to dump directory files. The flaw is tracked under CWE-74: Improper Neutralization of Special Elements in Output.

Critical Impact
A local low-privileged user can manipulate the contents of files written by root into ABRT crash dump directories, undermining the integrity of crash data and downstream tooling that consumes it.

Affected Products

libreport ABRT post-create event handler scripts
Red Hat Enterprise Linux distributions packaging the affected libreport component
Downstream Linux distributions consuming the upstream libreport event scripts

Discovery Timeline

2026-06-13 - CVE-2026-54231 published to the National Vulnerability Database
2026-06-17 - Last updated in the NVD database

Technical Details for CVE-2026-54231

Vulnerability Analysis

The vulnerability resides in the ABRT post-create event handler scripts provided by libreport. When a process crashes, ABRT invokes a post-create event that queries systemd-journald for journal entries associated with the crashed process. The script writes the returned journal text directly into files inside the dump directory, which is owned and written by root.

Because the script does not neutralize control characters in journal output, a local user who can emit syslog messages can embed newline sequences within those messages. When ABRT later harvests the journal and writes results to disk, the attacker-controlled newlines split the output into attacker-defined lines. The attacker effectively dictates the contents of file lines that appear to originate from the privileged ABRT pipeline.

The impact is limited to integrity. The CVSS vector indicates no confidentiality or availability impact, but high impact to integrity of data written by root into the dump directory.

Root Cause

The root cause is missing output neutralization in the ABRT post-create event scripts. The scripts trust journal field contents as opaque text rather than treating them as untrusted input requiring sanitization of newlines, carriage returns, and other control characters before being written to files.

Attack Vector

Exploitation requires local access and the ability to write to the systemd journal, which is available to any authenticated local user through standard syslog facilities. The attacker triggers or waits for a crash that ABRT will process, having first injected crafted syslog messages containing newline-separated payloads. The ABRT post-create handler then queries the journal and writes the attacker-controlled content into root-owned dump directory files. No user interaction is required beyond the attacker's own syslog write. See the Red Hat CVE-2026-54231 advisory and the Red Hat Bug Report #2488571 for additional technical context.

Detection Methods for CVE-2026-54231

Indicators of Compromise

Crash dump files in ABRT dump directories containing unexpected multi-line content attributable to a single journal entry.
Syslog or journal entries from non-root local users that contain embedded newline or carriage return byte sequences.
ABRT-generated files whose lines do not correspond to the canonical journal field formatting used by systemd-journald.

Detection Strategies

Audit syslog and journalctl output for messages containing raw \n or \r bytes originating from non-root UIDs.
Compare files written by ABRT post-create handlers against the raw journal export for the same time window to identify formatting anomalies.
Enable Linux audit rules on the ABRT dump directory path to track file writes and correlate them with journal authors.

Monitoring Recommendations

Forward journald and ABRT dump directory file events to a centralized log platform for cross-correlation.
Alert on local user accounts emitting syslog messages with embedded control characters at unusual rates.
Track creation of new ABRT dump directories and review their post-create handler output for injected content patterns.

How to Mitigate CVE-2026-54231

Immediate Actions Required

Apply vendor updates for libreport as soon as patched packages are available from your Linux distribution.
Review existing ABRT dump directories for content anomalies that may indicate prior exploitation.
Restrict local shell access on multi-user systems to reduce the population of users able to write to the journal.

Patch Information

At the time of publication, refer to the Red Hat CVE-2026-54231 advisory and the Red Hat Bug Report #2488571 for the current fix status and updated libreport package versions. Apply distribution updates through your standard package manager once the fixed libreport build is published.

Workarounds

Disable or remove the affected ABRT post-create event handler scripts on systems where automatic crash collection is not required.
Restrict membership of groups permitted to read or process ABRT dump directories so injected content cannot be leveraged by downstream tooling.
Configure log processing tools that consume ABRT dump directory files to treat the content as untrusted and to neutralize control characters before further parsing.

bash

# Configuration example: temporarily disable ABRT post-create journal harvesting
sudo systemctl stop abrtd
sudo systemctl disable abrtd
# Re-enable after applying the patched libreport package
sudo dnf update libreport
sudo systemctl enable --now abrtd