CVE-2026-77696
Last modified
CVE-2026-77696 is a low-severity vulnerability rated 3.7/10 on the CVSS scale. 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.. EPSS estimates a 0.24% chance of exploitation in the next 30 days.
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.
Metrics
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Openssl | Openssl | >= 1.1.1, < 1.1.1zj |
| Openssl | Openssl | >= 3.0.0, < 3.0.23 |
| Openssl | Openssl | >= 3.4.0, < 3.4.8 |
| Openssl | Openssl | >= 3.5.0, < 3.5.9 |
| Openssl | Openssl | >= 3.6.0, < 3.6.5 |
| Openssl | Openssl | >= 4.0.0, < 4.0.3 |
References
- https://openssl-library.org/news/secadv/20260929.txtVendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
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How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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