# CVE-2026-54872: Timing Side-Channel in Scalar Multiplication for Non-NIST EC Curves CVE-2026-54872 is fixed in 22 products on 1 platform, first by libssl3t64 3.5.5-1ubuntu3.6, released September 28, 2026. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2026-54872 - Priority: Routine - CVSS: 3.7 (Low) - EPSS: 0.0044 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Sep 28, 2026 - Weakness: Observable Timing Discrepancy - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-54872 ## Description Issue summary: The generic elliptic-curve scalar multiplication used for ECDSA and SM2 signature operations with curves that do not have a dedicated implementation leaks information about the secret nonce through timing. Impact summary: An attacker able to measure signing times may learn information about the per-signature secret nonce, which over many signatures can, via a lattice / Hidden Number Problem attack, lead to recovery of the private key. CWE: CWE-208: Observable Timing Discrepancy Description: The generic elliptic-curve scalar multiplication used for curves that do not have a dedicated constant-time implementation pads the secret scalar with non-constant-time BIGNUM operations, so the time taken depends on the value of the secret scalar derived from the ECDSA and SM2 nonce. The leak is very small; observing it requires a large number of measurements. The effect is largest for curves whose group order lies on a machine-word boundary, such as brainpoolP384r1. Applications using ECDSA signing over the Brainpool and other generic prime curves, and SM2 signing on platforms that use the generic implementation, are vulnerable to this issue. The NIST curves P-256, P-384 and P-521 use dedicated constant-time implementations and are not affected. FIPS Impact: no The FIPS modules are not affected: the approved NIST curves used in the FIPS provider have dedicated constant-time implementations and do not use the affected code path. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | edk2-aarch64 amzn 2023 | 20260508-2.amzn2023 | [ALAS2023-2026-3227](https://patchblox.com/security/data/fix/linux/alas2023-2026-3227.md) | Nov 7, 2026 | | Linux | edk2-ovmf amzn 2023 | 20260508-2.amzn2023 | [ALAS2023-2026-3227](https://patchblox.com/security/data/fix/linux/alas2023-2026-3227.md) | Nov 7, 2026 | | Linux | edk2-shell-aa64 amzn 2023 | 20260508-2.amzn2023 | [ALAS2023-2026-3227](https://patchblox.com/security/data/fix/linux/alas2023-2026-3227.md) | Nov 7, 2026 | | Linux | edk2-shell-x64 amzn 2023 | 20260508-2.amzn2023 | [ALAS2023-2026-3227](https://patchblox.com/security/data/fix/linux/alas2023-2026-3227.md) | Nov 7, 2026 | | Linux | libssl1.0.0 Ubuntu 18.04.6 LTS (bionic) | 1.0.2n-1ubuntu5.13+esm7 | [libssl1.0.0 1.0.2n-1ubuntu5.13+esm7](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libssl1.0.0-1.0.2n-1ubuntu5.13-esm7.md) | Oct 1, 2026 | | Linux | libssl1.1 Ubuntu 18.04.6 LTS (bionic) | 1.1.1-1ubuntu2.1~18.04.23+esm11 | [libssl1.1 1.1.1-1ubuntu2.1~18.04.23+esm11](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libssl1.1-1.1.1-1ubuntu2.1-18.04.23-esm11.md) | Oct 1, 2026 | | Linux | libssl1.1 Ubuntu 20.04 LTS (focal) | 1.1.1f-1ubuntu2.24+esm6 | [libssl1.1 1.1.1f-1ubuntu2.24+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libssl1.1-1.1.1f-1ubuntu2.24-esm6.md) | Oct 1, 2026 | | Linux | libssl3 Ubuntu 22.04.1 LTS (jammy) | 3.0.2-0ubuntu1.30 | [libssl3 3.0.2-0ubuntu1.30](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libssl3-3.0.2-0ubuntu1.30.md) | Sep 30, 2026 | | Linux | libssl3t64 Ubuntu 24.04.5 LTS (noble) | 3.0.13-0ubuntu3.16 | [libssl3t64 3.0.13-0ubuntu3.16](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libssl3t64-3.0.13-0ubuntu3.16.md) | Sep 30, 2026 | | Linux | libssl3t64 Ubuntu 26.04.1 LTS (resolute) | 3.5.5-1ubuntu3.6 | [libssl3t64 3.5.5-1ubuntu3.6](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libssl3t64-3.5.5-1ubuntu3.6.md) | Sep 28, 2026 | | Linux | openssl Debian 12.15 (bookworm) | 3.0.22-1~deb12u2 | [DEBIAN-CVE-2026-54872](https://patchblox.com/security/data/fix/linux/debian-cve-2026-54872.md) | Sep 30, 2026 | | Linux | openssl Debian 13.5 (trixie) | 3.5.7-1~deb13u3 | [DEBIAN-CVE-2026-54872](https://patchblox.com/security/data/fix/linux/debian-cve-2026-54872.md) | Sep 30, 2026 | | Linux | openssl Debian 14 | 3.6.5-1 | [DEBIAN-CVE-2026-54872](https://patchblox.com/security/data/fix/linux/debian-cve-2026-54872.md) | Sep 30, 2026 | | Linux | openssl Ubuntu 18.04.6 LTS (bionic) | 1.1.1-1ubuntu2.1~18.04.23+esm11 | [openssl 1.1.1-1ubuntu2.1~18.04.23+esm11](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-openssl-1.1.1-1ubuntu2.1-18.04.23-esm11.md) | Oct 1, 2026 | | Linux | openssl Ubuntu 20.04 LTS (focal) | 1.1.1f-1ubuntu2.24+esm6 | [openssl 1.1.1f-1ubuntu2.24+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-focal-openssl-1.1.1f-1ubuntu2.24-esm6.md) | Oct 1, 2026 | | Linux | openssl Ubuntu 22.04.1 LTS (jammy) | 3.0.2-0ubuntu1.30 | [openssl 3.0.2-0ubuntu1.30](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-openssl-3.0.2-0ubuntu1.30.md) | Sep 30, 2026 | | Linux | openssl Ubuntu 24.04.5 LTS (noble) | 3.0.13-0ubuntu3.16 | [openssl 3.0.13-0ubuntu3.16](https://patchblox.com/security/data/fix/linux/ubuntu-noble-openssl-3.0.13-0ubuntu3.16.md) | Sep 30, 2026 | | Linux | openssl Ubuntu 26.04.1 LTS (resolute) | 3.5.5-1ubuntu3.6 | [openssl 3.5.5-1ubuntu3.6](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-openssl-3.5.5-1ubuntu3.6.md) | Sep 28, 2026 | | Linux | openssl amzn 2023 | 1:3.5.8-1.amzn2023.0.3 | [ALAS2023-2026-3204](https://patchblox.com/security/data/fix/linux/alas2023-2026-3204.md) | Nov 7, 2026 | | Linux | openssl-3 opensuse-leap 16.0 | 3.5.0-160000.11.1 | [OPENSUSE-SU-2026:22102-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22102-1.md) | Nov 7, 2026 | | Linux | openssl-3 sles 15.6 | 3.1.4-150600.5.67.1 | [SUSE-SU-2026:4419-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4419-1.md) | Oct 2, 2026 | | Linux | openssl-3 sles 15.7 | 3.5.0-150700.5.53.2 | [SUSE-SU-2026:4414-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4414-1.md) | Oct 2, 2026 | | Linux | openssl-3 sles 16.0 | 3.5.0-160000.11.1 | [SUSE-SU-2026:24245-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24245-1.md) | Nov 7, 2026 | | Linux | openssl-debuginfo amzn 2023 | 1:3.5.8-1.amzn2023.0.3 | [ALAS2023-2026-3204](https://patchblox.com/security/data/fix/linux/alas2023-2026-3204.md) | Nov 7, 2026 | | Linux | openssl-debugsource amzn 2023 | 1:3.5.8-1.amzn2023.0.3 | [ALAS2023-2026-3204](https://patchblox.com/security/data/fix/linux/alas2023-2026-3204.md) | Nov 7, 2026 | | Linux | openssl-devel amzn 2023 | 1:3.5.8-1.amzn2023.0.3 | [ALAS2023-2026-3204](https://patchblox.com/security/data/fix/linux/alas2023-2026-3204.md) | Nov 7, 2026 | | Linux | openssl-fips-provider-latest amzn 2023 | 1:3.5.8-1.amzn2023.0.3 | [ALAS2023-2026-3204](https://patchblox.com/security/data/fix/linux/alas2023-2026-3204.md) | Nov 7, 2026 | | Linux | openssl-fips-provider-latest-debuginfo amzn 2023 | 1:3.5.8-1.amzn2023.0.3 | [ALAS2023-2026-3204](https://patchblox.com/security/data/fix/linux/alas2023-2026-3204.md) | Nov 7, 2026 | | Linux | openssl-libs amzn 2023 | 1:3.5.8-1.amzn2023.0.3 | [ALAS2023-2026-3204](https://patchblox.com/security/data/fix/linux/alas2023-2026-3204.md) | Nov 7, 2026 | | Linux | openssl-libs-debuginfo amzn 2023 | 1:3.5.8-1.amzn2023.0.3 | [ALAS2023-2026-3204](https://patchblox.com/security/data/fix/linux/alas2023-2026-3204.md) | Nov 7, 2026 | | Linux | openssl-perl amzn 2023 | 1:3.5.8-1.amzn2023.0.3 | [ALAS2023-2026-3204](https://patchblox.com/security/data/fix/linux/alas2023-2026-3204.md) | Nov 7, 2026 | | Linux | openssl-provider-legacy Ubuntu 26.04.1 LTS (resolute) | 3.5.5-1ubuntu3.6 | [openssl-provider-legacy 3.5.5-1ubuntu3.6](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-openssl-provider-legacy-3.5.5-1ubuntu3.6.md) | Sep 28, 2026 | | Linux | openssl-snapsafe-libs amzn 2023 | 1:3.5.8-1.amzn2023.0.3 | [ALAS2023-2026-3204](https://patchblox.com/security/data/fix/linux/alas2023-2026-3204.md) | Nov 7, 2026 | | Linux | openssl-snapsafe-libs-debuginfo amzn 2023 | 1:3.5.8-1.amzn2023.0.3 | [ALAS2023-2026-3204](https://patchblox.com/security/data/fix/linux/alas2023-2026-3204.md) | Nov 7, 2026 | | Linux | openssl1.0 Ubuntu 18.04.6 LTS (bionic) | 1.0.2n-1ubuntu5.13+esm7 | [openssl1.0 1.0.2n-1ubuntu5.13+esm7](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-openssl1.0-1.0.2n-1ubuntu5.13-esm7.md) | Oct 1, 2026 | --- Data as of 2026-11-08T00:53:09Z UTC. 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