CVE-2025-9231: OpenSSL

Medium severity, CVSS 6.5. EPSS: 2.2% chance of exploitation in the next 30 days.

Issue summary: A timing side-channel which could potentially allow remote recovery of the private key exists in the SM2 algorithm implementation on 64 bit ARM platforms. Impact summary: A timing side-channel in SM2 signature computations on 64 bit ARM platforms could allow recovering the private key by an attacker.. While remote key recovery over a network was not attempted by the reporter, timing measurements revealed a timing signal which may allow such an attack. OpenSSL does not directly support certificates with SM2 keys in TLS, and so this CVE is not relevant in most TLS contexts. However, given that it is possible to add support for such certificates via a custom provider, coupled with the fact that in such a custom provider context the private key may be recoverable via remote timing measurements, we consider this to be a Moderate severity issue. The FIPS modules in 3.5, 3.4, 3.3, 3.2, 3.1 and 3.0 are not affected by this issue, as SM2 is not an approved algorithm.

Affected products

  • OpenSSL OpenSSL: from 3.5.0, before 3.5.4 (fixed in 3.5.4); from 3.4.0, before 3.4.3 (fixed in 3.4.3); from 3.3.0, before 3.3.5 (fixed in 3.3.5); from 3.2.0, before 3.2.6 (fixed in 3.2.6)
  • Siemens Ruggedcom RST2428P: before V3.3 (fixed in V3.3); before V4.0 (fixed in V4.0)
  • Siemens Scalance Xc-300/xr-300/xc-400/xr-500wg/xr-500 Family: before V3.3 (fixed in V3.3)
  • Siemens Scalance XCH328: before V3.3 (fixed in V3.3)
  • Siemens Scalance XCM324: before V3.3 (fixed in V3.3)
  • Siemens Scalance XCM328: before V3.3 (fixed in V3.3)
  • Siemens Scalance XCM332: before V3.3 (fixed in V3.3)
  • Siemens Scalance XRH334 24 V Dc, 8xfo, Cc: before V3.3 (fixed in V3.3)
  • Siemens Scalance XRM334 230 V Ac, 12xfo: before V3.3 (fixed in V3.3)
  • Siemens Scalance XRM334 230 V Ac, 8xfo: before V3.3 (fixed in V3.3)
  • Siemens Scalance XRM334 230v Ac, 2x10g, 24xsfp, 8xsfp+: before V3.3 (fixed in V3.3)
  • Siemens Scalance XRM334 24 V Dc, 12xfo: before V3.3 (fixed in V3.3)
  • Siemens Scalance XRM334 24 V Dc, 8xfo: before V3.3 (fixed in V3.3)
  • Siemens Scalance XRM334 24v Dc, 2x10g, 24xsfp, 8xsfp+: before V3.3 (fixed in V3.3)
  • Siemens Scalance XRM334 2x230 V Ac, 12xfo: before V3.3 (fixed in V3.3)
  • Siemens Scalance XRM334 2x230 V Ac, 8xfo: before V3.3 (fixed in V3.3)
  • Siemens Scalance XRM334 2x230v Ac, 2x10g, 24xsfp, 8xsfp+: before V3.3 (fixed in V3.3)
  • Siemens Sidis Secured Smartplug: before V7.26.0310 (fixed in V7.26.0310)
  • Siemens SIMATIC Cn 4100: before V5.0 (fixed in V5.0)

Published 2025-09-30. Last modified 2026-07-14.