CVE-2022-26129 in FRRouting
Summary
by MITRE • 03/03/2022
Buffer overflow vulnerabilities exist in FRRouting through 8.1.0 due to wrong checks on the subtlv length in the functions, parse_hello_subtlv, parse_ihu_subtlv, and parse_update_subtlv in babeld/message.c.
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Analysis
by VulDB Data Team • 11/05/2025
The CVE-2022-26129 vulnerability represents a critical buffer overflow condition within FRRouting software version 8.1.0 and earlier, specifically affecting the Babel routing protocol implementation. This vulnerability stems from insufficient validation of subtlv length parameters within three key parsing functions located in the babeld/message.c file. The affected functions include parse_hello_subtlv, parse_ihu_subtlv, and parse_update_subtlv, which are responsible for processing various types of Babel protocol messages. These functions fail to properly validate the length of subtlv (sub-TLV) structures, creating opportunities for attackers to craft maliciously formatted packets that can trigger memory corruption. The vulnerability occurs during the parsing of routing update messages, hello messages, and interface hello messages that are fundamental to the Babel routing protocol's operation. When these functions process malformed subtlv data, they do not adequately verify that the specified length values align with the actual available buffer space, allowing for potential overflow conditions that can be exploited to execute arbitrary code or cause denial of service.
The technical exploitation of this vulnerability requires an attacker to send specially crafted Babel protocol messages to a vulnerable FRRouting instance. The buffer overflow occurs because the parsing functions do not perform proper bounds checking before copying data into fixed-size buffers. This flaw aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-787, which covers out-of-bounds write vulnerabilities. The attack vector is network-based, requiring the target system to be actively processing Babel routing messages from the attacker. The vulnerability can be leveraged through the Babel routing protocol's normal operational channels, making it particularly dangerous in network environments where Babel is actively used for dynamic routing. The operational impact extends beyond simple denial of service, as successful exploitation can lead to complete system compromise, allowing attackers to execute arbitrary code with the privileges of the routing daemon process. This represents a significant threat to network infrastructure security, particularly in environments where FRRouting is deployed as a core routing component.
The mitigation strategies for CVE-2022-26129 primarily involve upgrading to FRRouting version 8.2.0 or later, which contains the necessary patches to address the buffer overflow conditions in the affected parsing functions. Organizations should also implement network segmentation and access controls to limit exposure to potentially malicious Babel routing traffic, particularly in environments where the protocol is not strictly required. Monitoring network traffic for anomalous Babel protocol messages can help detect potential exploitation attempts, while implementing intrusion detection systems can provide additional layers of defense. The vulnerability demonstrates the importance of proper input validation in network protocol implementations and aligns with ATT&CK technique T1059.007, which covers command and scripting interpreter usage, as exploitation may involve crafting malicious routing updates. System administrators should also consider disabling Babel routing protocol on systems where it is not required, reducing the attack surface. The fix implemented in newer versions addresses the root cause by introducing proper bounds checking mechanisms within the parsing functions, ensuring that subtlv length parameters are validated against available buffer space before any data copying operations occur. This vulnerability serves as a reminder of the critical importance of robust input validation in network security implementations and the potential consequences of inadequate bounds checking in protocol parsers.