Issue summary: SM2 signature generation uses non-constant-time arithmetic
on secret values, forming a timing side-channel.
Impact summary: An attacker able to measure SM2 signing times may learn
information about the per-signature secret nonce, which over many signatures
can, via a lattice / Hidden Number Problem attack, lead to recovery of the
private key.
CWE: CWE-208: Observable Timing Discrepancy
Description: SM2 signature generation computes the signature value using
variable-time BIGNUM operations on the secret nonce and the private key, so
the time taken to produce an SM2 signature depends on these secret values,
forming a timing side-channel.
Applications performing SM2 signature generation are affected on all
platforms.
FIPS Impact: no
SM2 is not a FIPS algorithm.
on secret values, forming a timing side-channel.
Impact summary: An attacker able to measure SM2 signing times may learn
information about the per-signature secret nonce, which over many signatures
can, via a lattice / Hidden Number Problem attack, lead to recovery of the
private key.
CWE: CWE-208: Observable Timing Discrepancy
Description: SM2 signature generation computes the signature value using
variable-time BIGNUM operations on the secret nonce and the private key, so
the time taken to produce an SM2 signature depends on these secret values,
forming a timing side-channel.
Applications performing SM2 signature generation are affected on all
platforms.
FIPS Impact: no
SM2 is not a FIPS algorithm.
Metrics
Affected Vendors & Products
No data.
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Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Tue, 29 Sep 2026 15:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Issue summary: SM2 signature generation uses non-constant-time arithmetic on secret values, forming a timing side-channel. Impact summary: An attacker able to measure SM2 signing times may learn information about the per-signature secret nonce, which over many signatures can, via a lattice / Hidden Number Problem attack, lead to recovery of the private key. CWE: CWE-208: Observable Timing Discrepancy Description: SM2 signature generation computes the signature value using variable-time BIGNUM operations on the secret nonce and the private key, so the time taken to produce an SM2 signature depends on these secret values, forming a timing side-channel. Applications performing SM2 signature generation are affected on all platforms. FIPS Impact: no SM2 is not a FIPS algorithm. | |
| Title | Timing Side-Channel in SM2 Signature Generation | |
| Weaknesses | CWE-208 | |
| References |
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Projects
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MITRE
Status: PUBLISHED
Assigner: openssl
Published:
Updated: 2026-09-29T15:32:22.520Z
Reserved: 2026-08-21T07:47:36.032Z
Link: CVE-2026-77696
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
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Weaknesses