Overview
CVE-2025-13735 describes a high-severity out-of-bounds read vulnerability discovered in ASR Lapwing_Linux, specifically affecting ASR1903 and ASR3901 devices. This vulnerability resides within the nr_fw modules on Linux and stems from an issue in the Code/nr_fw/DLP/src/NrCgi.C program file. This flaw could potentially allow an attacker to read sensitive information from system memory, leading to further exploitation.
The vulnerability affects Lapwing_Linux versions prior to the patch released on 2025/11/26.
Technical Details
The root cause of CVE-2025-13735 lies in how the NrCgi.C file handles certain input parameters within the DLP (Data Loss Prevention) component of the nr_fw modules. Specifically, the code lacks proper bounds checking when accessing data structures, allowing an attacker to potentially provide crafted input that leads to reading data beyond the allocated memory region. This out-of-bounds read can expose sensitive data that should not be accessible.
Exploitation of this vulnerability could involve sending specially crafted network packets or manipulating other input mechanisms that interact with the vulnerable code.
CVSS Analysis
The Common Vulnerability Scoring System (CVSS) v3.0 score for CVE-2025-13735 is 7.4 (HIGH).
- Attack Vector (AV): Network (N)
- Attack Complexity (AC): High (H)
- Privileges Required (PR): None (N)
- User Interaction (UI): None (N)
- Scope (S): Unchanged (U)
- Confidentiality Impact (C): High (H)
- Integrity Impact (I): None (N)
- Availability Impact (A): None (N)
The high confidentiality impact indicates that successful exploitation can lead to significant exposure of sensitive information.
Possible Impact
Successful exploitation of CVE-2025-13735 could have several serious consequences:
- Information Disclosure: An attacker could read sensitive data from memory, including configuration files, cryptographic keys, or other confidential information.
- Privilege Escalation (Potential): While the CVSS score doesn’t directly indicate integrity impact, the information gained from the out-of-bounds read could potentially be used to further escalate privileges or compromise the system further.
- System Instability (Less Likely): While not the primary impact, repeatedly triggering the vulnerability could potentially lead to system instability or crashes, although this is less likely given the ‘Read’ nature of the vulnerability.
Mitigation or Patch Steps
The primary mitigation strategy is to apply the official patch released by ASR Microelectronics:
- Apply the Patch: Upgrade Lapwing_Linux to version 2025/11/26 or later. Contact your vendor for specific update instructions.
- Workarounds (If Patching is Not Immediately Possible): If immediate patching is not feasible, consider the following (with caution and thorough testing):
- Network Segmentation: Isolate affected devices from the broader network to limit the potential impact of a successful attack.
- Input Validation: Implement strict input validation on data processed by the
nr_fwmodules, specifically focusing on parameters handled byNrCgi.C. This is a temporary measure and should not replace the official patch. This requires advanced knowledge of the system and is not recommended without significant expertise.
