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MEDIUM

Timing side-channel in SM2 algorithm on 64 bit ARM

Published Sep 30, 2025

Description

Issue summary: A timing side-channel which could potentially allow remote recovery of the private key exists in the SM2 algorithm implementation on 64 bit ARM platforms.

Impact summary: A timing side-channel in SM2 signature computations on 64 bit ARM platforms could allow recovering the private key by an attacker..

While remote key recovery over a network was not attempted by the reporter, timing measurements revealed a timing signal which may allow such an attack.

OpenSSL does not directly support certificates with SM2 keys in TLS, and so this CVE is not relevant in most TLS contexts. However, given that it is possible to add support for such certificates via a custom provider, coupled with the fact that in such a custom provider context the private key may be recoverable via remote timing measurements, we consider this to be a Moderate severity issue.

The FIPS modules in 3.5, 3.4, 3.3, 3.2, 3.1 and 3.0 are not affected by this issue, as SM2 is not an approved algorithm.

Affected products

Remediation

Red Hat statement

The vulnerability was rated as Moderate because, while it could enable recovery of private keys through timing side-channel analysis on 64-bit ARM platforms, successful exploitation requires high-precision timing measurements and a specialized attack setup. OpenSSL does not natively support SM2 certificates in TLS, limiting the exposure in common use cases. The issue only becomes relevant in custom provider contexts where SM2 is enabled, further reducing the likelihood of widespread impact. Therefore, although the confidentiality impact is high if exploited, the practical attack complexity and limited applicability justify a Moderate severity rating.

Red Hat mitigation

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Weaknesses (2)

CWE-208

CWE-385

References (15)

Change history (0)

No recorded changes yet.

Sources
CVE.org / MITRE
Status PUBLISHED
Assigner openssl
Published Sep 30, 2025
Updated Jul 14, 2026
Reserved Aug 20, 2025
Link CVE-2025-9231
CISA Vulnrichment
Updated Sep 30, 2025
NVD
Status Deferred
Modified Jul 14, 2026
Link CVE-2025-9231
Red Hat
Severity Moderate
Public date Sep 30, 2025
Links CVE-2025-9231 - Bugzilla
ENISA EUVD
Assigner n/a
Published n/a
Updated n/a
Exploited since n/a
Link n/a