CVE-2026-54875

Issue summary: A non-constant-time optimized implementation of scalar point multiplication is used…

Risk score: 40/100
CVSS: 3.7 v3.1
Exploit chance (30 days): 0.5%
Published: 29 Sep 2026

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What to know

What it is: 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 platfor…
Affected: OpenSSL
Fix: Apply the vendor's security update; see the linked advisory.
Exploitation: No known exploitation

Story map

Story map: the flaws, the fix, how it unfolded and what it connects to. Boxes link to the record or article.

At a glance

OpenSSL: Amber, patch this week. Issue summary: The DTLS retransmission logic does not correctly handle a handshake message write that is suspended part-way through. The retransmitted message can be read past the message buffer and the retransmission overwrites the internal state the suspended write needs to resume correctly. Impact summary: The retr…

The flaws

CVE-2026-54875: Issue summary: A non-constant-time optimized implementation of scalar point multiplication is used… (CVSS 3.7 · EPSS 0%)
CVE-2026-84782: Out-of-bounds read can lead to denial of service (CVSS 8.2 · EPSS 1%)
CVE-2026-54873: Denial of service (CVSS 7.5 · EPSS 1%)
CVE-2026-84784: Denial of service (CVSS 7.5 · EPSS 1%)

The fix

Fix: Apply the vendor's security update; see the linked advisory.

Who is exposed: OpenSSL

Where it stands

No known exploitation

Connects to

Same weakness: CWE-208 (CWE-208). 5 other warnings in 30 days
Same product: Earlier OpenSSL warnings. 10 in the last 90 days

Why it is Yellow

CVSS 3.7 low
On your watchlist: openssl

References

Original 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

Last activity 29 Sep 2026. Patch Forecast updates every hour.