Variable Time Instruction Vulnerability in Go Runtime for ppc64le Architecture

CVE-2025-22866

What is CVE-2025-22866?

CVE-2025-22866 is a vulnerability found in the Go Standard Library, specifically affecting the ppc64le architecture. This vulnerability stems from the use of variable time instructions within the assembly implementation of an internal function, which could potentially lead to the unintentional leakage of a limited number of bits from secret scalars. While the architecture is commonly employed in various applications, this flaw could expose sensitive cryptographic materials if exploited. Although the leakage is not believed to be sufficient for private key recovery in typical scenarios like using the P-256 curve in well-known protocols, it nonetheless presents a security risk that organizations utilizing the Go programming language need to be aware of.

Technical Details

The vulnerability involves the assembly implementation of a specific internal function within the Go runtime on ppc64le architecture, which executes operations that might leak secret information through timing variations. Such a vulnerability arises from the inherent characteristics of variable time instructions, where the execution time may vary based on the values being processed. This can lead to information disclosure if an attacker is able to observe these timing differences. The developers have analyzed the function's usage patterns, concluding that the information leakage is not substantial enough to facilitate the recovery of private keys within standard cryptographic protocols.

Potential Impact of CVE-2025-22866

1. Information Leakage: The most pressing impact of CVE-2025-22866 is the potential for secret scalar leakage, which could compromise the confidentiality of cryptographic operations. Even a small amount of leaked information can provide insights or footholds for more extensive attacks.

2. Cryptographic Vulnerability: While the vulnerability does not allow for the easy recovery of private keys under typical usage, it raises alarms about the overall resilience of cryptographic implementations on affected architectures. This could lead to a lack of trust in systems relying on Go for secure communications.

3. Risk to Applications: Applications built on the Go Standard Library that utilize the ppc64le architecture may face increased scrutiny and additional security reviews if this vulnerability remains unaddressed. Organizations may need to reassess their security posture if they are reliant on this architecture for sensitive applications.

References