SM2 scalar leakage via secret-dependent multiplication
Published Sep 29, 2026 · Updated Sep 29, 2026
Information disclosure in OpenSSL SM2 operations on ARM64 and RISC-V allows attackers to infer secret scalars through timing or cache access. The optimized ecp_sm2p256 scalar-multiplication path branches and selects table entries according to secret scalar bits. Exposure requires SM2 signing or decryption on an affected build and access to timing measurements or cache observations; the leaked information concerns a signing nonce or decryption key.
Summary
What happened
Information disclosure in OpenSSL SM2 operations on ARM64 and RISC-V allows attackers to infer secret scalars through timing or cache access. The optimized ecp_sm2p256 scalar-multiplication path branches and selects table entries according to secret scalar bits. Exposure requires SM2 signing or decryption on an affected build and access to timing measurements or cache observations; the leaked information concerns a signing nonce or decryption key.
The record
- CVE
- CVE-2026-54875
- Published
- Sep 29, 2026
- Updated
- Sep 29, 2026
- Vendor
- OpenSSL Project
- Product
- OpenSSL
- Classifications
- CWE-208
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 29, 2026CVE publishedPublication date reported by the CVE source.
- Sep 29, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=3.4.0 <3.4.8
- Affected versionversion=3.5.0 <3.5.9
- Affected versionversion=3.6.0 <3.6.5
- Affected versionversion=4.0.0 <4.0.3
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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