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Vulnerabilities

Vulnerability · CVE-2026-54875

Non-Constant-Time SM2 Scalar Multiplication on ARM64 and RISC-V

Published Sep 29, 2026 · catalog updated Sep 29, 2026 · OpenSSL OpenSSL

Last checked Oct 27, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-54875. EPSS is 0.48%. Act only if a listed version of OpenSSL OpenSSL is installed.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Low3.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.48%
Remediation
Advisory link
Affected products
vendor OpenSSL OpenSSL

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

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

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  • vendor OpenSSL OpenSSLversion unspecified

How to fix CVE-2026-54875

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-54875. EPSS is 0.48%. Act only if a listed version of OpenSSL OpenSSL is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-208. EPSS 0.48%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Sep 29, 2026 · CVE.org

    Updated

    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

  2. Oct 27, 2026 · BSI CERT-Bund

    Detected

    CVE-2026-54875 is listed by OpenSSL: Mehrere Schwachstellen.

Sources

  • BSI CERT-BundGovernment advisoryCVE-2026-54875

    OpenSSL: Mehrere Schwachstellen

    wid.cert-bund.de
  • CVE.orgVulnerability recordCVE-2026-54875

    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 signi

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-54875

    30-day exploitation probability 0.48%

    first.org

References

Freshness

Last verified in this catalog Oct 27, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgOct 27, 2026
  • BSI CERT-BundOct 27, 2026
  • FIRST EPSSOct 27, 2026
CVE-2026-54875: OpenSSL OpenSSL — Non-Constant-Time SM2 Scalar Mult… · ZeroDay Findings