CVE-2024-48867: QNAP QTS CRLF Injection Vulnerability

CVE-2024-48867 Overview

CVE-2024-48867 is a Carriage Return Line Feed (CRLF) injection vulnerability affecting multiple versions of QNAP QTS and QuTS hero operating systems. The flaw stems from improper neutralization of CRLF sequences [CWE-93] in application input handling. Remote attackers can exploit the vulnerability to modify application data, provided a user is induced to interact with crafted input. QNAP addressed the issue in QTS 5.1.9.2954 build 20241120, QTS 5.2.2.2950 build 20241114, QuTS hero h5.1.9.2954 build 20241120, and QuTS hero h5.2.2.2952 build 20241116.

Critical Impact
Successful exploitation allows remote attackers to inject CRLF sequences and modify application data on affected QNAP network-attached storage (NAS) devices.

Affected Products

QNAP QTS versions prior to 5.1.9.2954 build 20241120
QNAP QTS 5.2.x versions prior to 5.2.2.2950 build 20241114
QNAP QuTS hero versions prior to h5.1.9.2954 build 20241120 and h5.2.2.2952 build 20241116

Discovery Timeline

2024-12-06 - CVE-2024-48867 published to the National Vulnerability Database (NVD)
2025-09-23 - Last updated in NVD database

Technical Details for CVE-2024-48867

Vulnerability Analysis

The vulnerability arises from improper neutralization of CRLF (\r\n) sequences in user-controlled input processed by QTS and QuTS hero. Attackers who inject raw CRLF characters can manipulate the structure of downstream protocol messages, log entries, or HTTP responses generated by the appliance. Because the attack vector is network-based and requires user interaction, exploitation typically involves a victim clicking or rendering a crafted link or payload directed at the NAS web interface. The resulting impact is limited to integrity and confidentiality of application data rather than full system compromise.

Root Cause

The root cause is missing input sanitization on fields that are later concatenated into protocol-level messages. When CRLF byte sequences pass through unfiltered, they break the intended message framing and let attackers append or alter fields the application later parses as authoritative data.

Attack Vector

An attacker delivers a crafted URL or input containing encoded CRLF sequences to an authenticated or about-to-authenticate user of the QNAP appliance. When the victim interacts with the payload, the embedded CRLF sequences alter how the QNAP web stack composes responses or stores data. The result can include HTTP response splitting, header injection, or modification of stored application records.

No public proof-of-concept or exploit code is currently available for CVE-2024-48867, and the issue is not listed in the CISA Known Exploited Vulnerabilities catalog. Refer to the QNAP Security Advisory QSA-24-49 for vendor technical details.

Detection Methods for CVE-2024-48867

Indicators of Compromise

Web server access logs on QTS or QuTS hero containing URL-encoded CRLF sequences such as %0d%0a, %0D%0A, or \r\n in query parameters or POST bodies.
Unexpected HTTP response headers appearing in NAS-generated responses, indicating possible response splitting.
Modified application records, configuration entries, or log lines that contain unexpected line breaks or injected fields.

Detection Strategies

Inspect HTTP traffic destined for QNAP management interfaces for raw or encoded CR (%0d) and LF (%0a) bytes in parameter values.
Correlate user-initiated navigation events with subsequent anomalous responses or configuration changes on the NAS.
Audit application and authentication logs for entries containing embedded newlines that could indicate log forging.

Monitoring Recommendations

Restrict and monitor administrative access to QNAP appliances from untrusted networks using firewall and VPN controls.
Forward QTS and QuTS hero logs to a centralized logging or SIEM platform for retention and anomaly analysis.
Alert on outbound requests from internal users to QNAP management URLs containing CRLF-encoded characters.

How to Mitigate CVE-2024-48867

Immediate Actions Required

Upgrade QTS to version 5.1.9.2954 build 20241120 or 5.2.2.2950 build 20241114 or later.
Upgrade QuTS hero to version h5.1.9.2954 build 20241120 or h5.2.2.2952 build 20241116 or later.
Restrict the QNAP web administration interface to trusted networks only and require VPN access for remote management.
Review NAS audit logs for evidence of CRLF-encoded input prior to patching.

Patch Information

QNAP released fixed builds documented in QNAP Security Advisory QSA-24-49. Administrators can apply updates through the QTS or QuTS hero Control Panel by navigating to System > Firmware Update and selecting Live Update, or by manually downloading firmware from the QNAP Download Center.

Workarounds

Disable remote access to the QNAP web interface from the internet until firmware is updated.
Place the NAS behind a reverse proxy or web application firewall (WAF) configured to strip or block CRLF byte sequences in request parameters.
Educate administrators to avoid clicking unsolicited links that target the NAS management interface.

bash

# Example WAF rule concept to block CRLF injection attempts in query strings
# (adapt to your WAF syntax; this is illustrative only)
SecRule REQUEST_URI|ARGS "@rx (?:%0d%0a|%0D%0A|\r\n)" \
    "id:1004886,phase:2,deny,status:400,msg:'CRLF injection attempt blocked (CVE-2024-48867)'"