Non-Constant-Time SM2 Scalar Multiplication on ARM64 and RISC-V
Summary
| CVE | CVE-2026-54875 |
|---|---|
| State | PUBLISHED |
| Assigner | openssl |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-29 16:17:08 UTC |
| Updated | 2026-09-29 21:27:41 UTC |
| Description | Issue summary: A non-constant-time optimized implementation of scalar point multiplication is used for SM2 private key operations on ARM64 and RISC-V platforms. Impact summary: An attacker able to measure the time taken by, or to observe the cache-line access pattern of SM2 signing or decryption on an affected platform can learn information about the secret scalar. CWE: CWE-208: Observable Timing Discrepancy Description: On ARM64 and RISC-V processors, the SM2 curve uses an optimized scalar multiplication implementation whose conditional branches and table look ups are chosen according to the bits of the secret scalar. The execution time and the cache-access pattern therefore depend on the long-term private key (during SM2 decryption) or the per-signature nonce (during SM2 signature generation), forming a timing and cache side-channel. FIPS Impact: no SM2 is not a FIPS algorithm and the optimized SM2 implementation is not part of the FIPS module. OpenSSL 4.0, 3.6, 3.5 and 3.4 are vulnerable to this issue on AArch64 and RISC-V. OpenSSL 3.0, 1.1.1 and 1.0.2 are not affected by this issue. OpenSSL 4.0 users should upgrade to OpenSSL 4.0.3. OpenSSL 3.6 users should upgrade to OpenSSL 3.6.5. OpenSSL 3.5 users should upgrade to OpenSSL 3.5.9. OpenSSL 3.4 users should upgrade to OpenSSL 3.4.8. This issue was reported on 2 May 2026 by Abhinav Agarwal. It was independently reported on 6 June 2026 by Feng Xue. The fix was developed by Igor Ustinov. -- cut (non-publishing metadata for internal use) -- Reported by: Abhinav Agarwal, Feng Xue Fixed by: Igor Ustinov |
Risk And Classification
Primary CVSS: v3.1 3.7 LOW from ADP
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Problem Types: CWE-208 | CWE-208 CWE-208 Observable Timing Discrepancy
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | ADP | DECLARED | 3.7 | LOW | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N |
| 3.1 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | Secondary | 3.7 | LOW | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
LowIntegrity
NoneAvailability
NoneCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/openssl/openssl/commit/dddad955d5ff3e9507619cf4e0f13e9988e2197c | [email protected] | github.com | |
| github.com/openssl/openssl/commit/9794ed473764839275cb701b4850f3c24d929c28 | [email protected] | github.com | |
| openssl-library.org/news/secadv/20260929.txt | [email protected] | openssl-library.org | |
| github.com/openssl/openssl/commit/3f01bbc28f7e08211fcdc797fd43816504f94257 | [email protected] | github.com | |
| github.com/openssl/openssl/commit/469f3e42629f4a0b5631796e20c66c92c138a3e8 | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Abhinav Agarwal (en)
CNA: Feng Xue (en)
CNA: Igor Ustinov (en)
There are currently no legacy QID mappings associated with this CVE.