Skip to content
Fencer Vulns
low 3.7

CVE-2026-54872 json

Timing Side-Channel in Scalar Multiplication for Non-NIST EC Curves

published 2026-09-29 40 d ago modified 2026-10-08 32 d ago also EUVD-2026-89004

cvss
3.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 38%
public exploits
0
none known

Summary

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.

Patch / fix

  • OpenSSL OpenSSL 1.0.2zs, 1.1.1zj, 3.0.23, 3.4.8, 3.5.9, 3.6.5, 4.0.3
  • openssl Debian 12 3.0.22-1~deb12u2
  • openssl Debian 13 3.5.7-1~deb13u3
  • openssl Debian 14 3.6.5-1

debian advisories DEBIAN-CVE-2026-54872

  • openssl Ubuntu 22.04 LTS 3.0.2-0ubuntu1.30
  • openssl Ubuntu 24.04 LTS 3.0.13-0ubuntu3.16
  • openssl Ubuntu 26.04 LTS 3.5.5-1ubuntu3.6
  • openssl Ubuntu Pro 14.04 LTS 1.0.1f-1ubuntu2.27+esm17
  • openssl Ubuntu Pro 16.04 LTS 1.0.2g-1ubuntu4.20+esm19
  • openssl Ubuntu Pro 18.04 LTS 1.1.1-1ubuntu2.1~18.04.23+esm11
  • openssl Ubuntu Pro 20.04 LTS 1.1.1f-1ubuntu2.24+esm6
  • openssl1.0 Ubuntu Pro 18.04 LTS 1.0.2n-1ubuntu5.13+esm7

ubuntu advisories UBUNTU-CVE-2026-54872

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • openssl3 hummingbird 1 3.5.9-0.1.hum1
  • openssl3-libs hummingbird 1 3.5.9-0.1.hum1
  • openssl3-devel-engine hummingbird 1 3.5.9-0.1.hum1
  • openssl hummingbird 1 3.5.9-0.1.hum1
  • openssl-libs hummingbird 1 3.5.9-0.1.hum1
  • openssl-perl hummingbird 1 3.5.9-0.1.hum1
  • openssl-config-fips hummingbird 1 3.5.9-0.1.hum1
  • openssl-devel-engine hummingbird 1 3.5.9-0.1.hum1

red hat advisories RHSA-2026:74166RHSA-2026:74162

  • openssl-3 Linux Micro 6.1 3.1.4-slfo.1.1_14.1
  • openssl-3 SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 3.5.0-160000.11.1
  • openssl-3 Linux Micro 6.0 3.1.4-159998.1.1
  • openssl-3 SLE Module for Basesystem 15 SP7 3.5.0-150700.5.53.2
  • openssl-3 SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +3 more 3.0.8-150400.4.101.1
  • openssl-3 SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 3.0.8-150500.5.80.1
  • openssl-3 SLES for SAP 15 SP6, SLES 15 SP6-LTSS 3.1.4-150600.5.67.1

suse advisories SUSE-SU-2026:24273-1SUSE-SU-2026:24188-1SUSE-SU-2026:24245-1SUSE-SU-2026:24133-1SUSE-SU-2026:4419-1SUSE-SU-2026:4414-1

  • openssl-3 openSUSE Leap 16.0 3.5.0-160000.11.1

opensuse advisories openSUSE-SU-2026:22102-1

  • openssl Alpine 3.21 3.3.7-r2

alpine advisories ALPINE-CVE-2026-54872

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • edk2 Azure Linux 3.0 20240524git3e722403cd16-21
  • openssl Azure Linux 3.0 3.3.7-7

azure linux advisories AZL-105480AZL-105573

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-54872 updated cvss 5.9

openssl: OpenSSL: Private key recovery via timing side-channel in generic elliptic curve operations

  • Red Hat Developer Hub 1 rhdh/rhdh-hub-rhel9
    affected: workaround, no fix available “Prefer NIST curves with dedicated constant-time implementations (P-256, P-384, P-521) for ECDSA. Avoid Brainpool and other generic prime curves for high-value signing where practical.”
  • Red Hat Enterprise Linux 6 openssl, openssl-perl, openssl 3.5.8-1.el10_2
    affected: workaround, no fix planned “Prefer NIST curves with dedicated constant-time implementations (P-256, P-384, P-521) for ECDSA. Avoid Brainpool and other generic prime curves for high-value signing where practical.”
  • Red Hat Enterprise Linux 7 ovmf, OVMF, shim, AAVMF, mokutil, openssl, +6 more Red Hat Enterprise Linux 8 openssl, shim-x64, edk2-ovmf, shim-aa64, shim-ia32, edk2-aarch64, +13 more Red Hat Enterprise Linux 9 openssl, shim-x64, shim-aa64, openssl-libs, openssl-perl, compat-openssl11, +5 more Red Hat Enterprise Linux 10 shim 16.1-4.el10, openssl 3.5.8-1.el10_2, edk2 20251114-5.el10_2.2, shim-unsigned-x64 16.1-1.el10, shim-unsigned-aarch64 16.1-2.el10 Red Hat JBoss Core Services jbcs-httpd24-openssl, jbcs-httpd24-openssl-libs, jbcs-httpd24-openssl-perl Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    +2 more products
    Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9 Red Hat Satellite 6 puppet-agent, openvox-agent 8.28.1-1.el9sat
    affected: workaround, no fix available “Prefer NIST curves with dedicated constant-time implementations (P-256, P-384, P-521) for ECDSA. Avoid Brainpool and other generic prime curves for high-value signing where practical.”
  • Red Hat Enterprise Linux 9 edk2-ovmf, edk2-tools, edk2-aarch64, edk2 20251114-5.el10_2.2 Red Hat OpenShift AI (RHOAI) rhoai/odh-core-bff-rhel9, rhoai/odh-dashboard-rhel9, rhoai/odh-mod-arch-maas-rhel9, rhoai/odh-mod-arch-automl-rhel9, rhoai/odh-mod-arch-gen-ai-rhel9, rhoai/odh-mod-arch-mlflow-rhel9, +6 more
    under investigation
  • Red Hat Hardened Images openssl 3.5.9-0.1.hum1, openssl3 3.5.9-0.1.hum1, openssl-libs 3.5.9-0.1.hum1, openssl-perl 3.5.9-0.1.hum1, openssl3-libs 3.5.9-0.1.hum1, openssl-config-fips 3.5.9-0.1.hum1, +3 more
    fixed: vendor fix “Prefer NIST curves with dedicated constant-time implementations (P-256, P-384, P-521) for ECDSA. Avoid Brainpool and other generic prime curves for high-value signing where practical.” RHSA-2026:74162
  • Red Hat Hardened Images unbound 1.26.1-1.hum1 Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9, rhoai/odh-kube-rbac-proxy-rhel9, rhoai/odh-maas-controller-rhel9, rhoai/odh-mlflow-operator-rhel9, rhoai/odh-model-controller-rhel9, rhoai/odh-ogx-k8s-operator-rhel9, +14 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
40 d ago

Exploit prediction

0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
CNA 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected products

  • OpenSSL OpenSSL

Classification

Weakness
  • CWE-208 Observable Timing Discrepancy
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.