CVE-2026-54875
Publication date 29 September 2026
Last updated 30 September 2026
Ubuntu priority
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
Read the notes from the security team
Why is this CVE low priority?
OpenSSL developers have rated this issue as being low severity
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| openssl | 26.04 LTS resolute |
Fixed 3.5.5-1ubuntu3.6
|
| 24.04 LTS noble |
Not affected
|
|
| 22.04 LTS jammy |
Not affected
|
|
| 20.04 LTS focal |
Not affected
|
|
| 18.04 LTS bionic |
Not affected
|
|
| 16.04 LTS xenial |
Not affected
|
|
| 14.04 LTS trusty |
Not affected
|
|
| openssl-fips | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble |
Not affected
|
|
| 22.04 LTS jammy |
Not affected
|
|
| openssl1.0 | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release | |
| 18.04 LTS bionic |
Not affected
|
|
| nodejs | 26.04 LTS resolute |
Not affected
|
| 24.04 LTS noble |
Not affected
|
|
| 22.04 LTS jammy |
Vulnerable
|
|
| 20.04 LTS focal |
Not affected
|
|
| 18.04 LTS bionic |
Not affected
|
|
| 16.04 LTS xenial |
Not affected
|
|
| 14.04 LTS trusty |
Not affected
|
|
| edk2 | 26.04 LTS resolute |
Vulnerable
|
| 24.04 LTS noble |
Not affected
|
|
| 22.04 LTS jammy |
Not affected
|
|
| 20.04 LTS focal |
Not affected
|
|
| 18.04 LTS bionic |
Not affected
|
|
| 16.04 LTS xenial |
Not affected
|
|
| edk2-hwe | 26.04 LTS resolute |
Vulnerable
|
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release |
Notes
mdeslaur
edk2 in jammy embeds OpenSSL 1.1.1j edk2 in noble embeds OpenSSL 3.0.9 edk2 in resolute embeds OpenSSL 3.5.1 edk2 in stonking embeds OpenSSL 3.5.1 nodejs in jammy embeds OpenSSL 1.1.1m 4.0, 3.6, 3.5 and 3.4 are vulnerable
Severity score breakdown
CVSS version: CVSS v3.0
Base score
3.7 · Low
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
References
Related Ubuntu Security Notices (USN)
- USN-8847-1
- OpenSSL vulnerabilities
- 29 September 2026