CVE-2026-116544 in Open5GS
Summary
by MITRE • 10/26/2026
Open5GS 2.6.1 through 2.8.0 contains an out-of-bounds read vulnerability in parse_scheme_output() in lib/sbi/conv.c during SUCI de-concealment due to incomplete length validation. Remote unauthenticated UEs or SBI peers can submit a crafted SUCI with a 42-byte scheme output to a UDM, triggering a heap over-read past the buffer.
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Analysis
by VulDB Data Team • 10/26/2026
The vulnerability identified in Open5GS versions 2.6.1 through 2.8.0 represents a critical security flaw within the Subscription Concealed Identifier de-concealment process. Specifically, the defect resides in the parse_scheme_output function located in the lib/sbi/conv.c source file. This component is responsible for processing SBI messages and handling cryptographic operations related to subscriber identity protection. The core technical issue stems from an incomplete length validation mechanism during the parsing of scheme output data. When a device or peer submits a crafted Subscription Concealed Identifier with exactly forty-two bytes in its scheme output field, the application fails to adequately verify that this input size aligns with expected buffer constraints before proceeding with memory operations.
This lack of rigorous bounds checking leads directly to an out-of-bounds read condition on the heap. During execution, the function attempts to access memory locations beyond the allocated buffer boundaries based on the malformed input length. This results in a heap over-read vulnerability where sensitive data from adjacent memory regions may be exposed or processed incorrectly. The severity of this issue is compounded by its remote exploitability and lack of authentication requirements. Any unauthenticated User Equipment attempting network attachment, as well as any Service Based Interface peer capable of sending SBI messages to the Unified Data Management function, can trigger this condition without prior authorization credentials.
From an operational perspective, exploiting this vulnerability allows attackers to potentially leak internal memory contents which may contain sensitive subscriber information, cryptographic keys, or other proprietary data structures used by the network core functions. While primarily classified as a read-based flaw rather than arbitrary code execution, such leaks can facilitate further attacks including credential theft, user tracking, and reconnaissance against the 5G core infrastructure. The impact extends beyond immediate confidentiality breaches to include potential denial of service if the malformed memory access causes application crashes or instability within the UDM process.
In terms of industry classification standards, this vulnerability aligns with CWE-125 which defines out-of-bounds read vulnerabilities resulting from improper validation of array indices or buffer lengths. Furthermore, given that it involves remote exploitation without authentication in a network-facing service, it maps to MITRE ATT&CK techniques associated with initial access and collection phases where adversaries gather data for subsequent lateral movement or exfiltration objectives within the 5G ecosystem.
Mitigation strategies should prioritize immediate patching of Open5GS to version 2.8.1 or later which addresses this specific validation gap. In environments where upgrading is not immediately feasible, network segmentation policies restricting direct SBI access from untrusted networks can reduce exposure. Additionally implementing strict input filtering at the perimeter firewall level to reject malformed SUCI structures with anomalous scheme output lengths provides a defensive layer against exploitation attempts until permanent remediation is applied.