Timing Side-Channel in Scalar Multiplication for Non-NIST EC Curves (CVE-2026-54872) | HOL Guard CVE

Low · CVSS 3.7CVE-2026-54872

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

Answer in brief

CVE-2026-54872 records a Low severity (CVSS 3.7) vulnerability in Timing Side-Channel in Scalar Multiplication for Non-NIST EC Curves. The current sources do not mark it as known exploited. The current feed maps OpenSSL/OpenSSL (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 29, 2026Updated Sep 29, 2026Source checked Sep 29, 2026First seen by HOL Sep 29, 2026Material review Sep 29, 2026

Upstream Advisory

Key facts

Risk: Low · CVSS 3.7
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 3.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps OpenSSL/OpenSSL (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
OpenSSL/OpenSSLgeneric	>=4.0.0 <4.0.3 \|\| >=3.6.0 <3.6.5 \|\| >=3.5.0 <3.5.9 \|\| >=3.4.0 <3.4.8 \|\| >=3.0.0 <3.0.23 \|\| >=1.1.1 <1.1.1zj \|\| >=1.0.2 <1.0.2zs	4.0.3, 3.6.5, 3.5.9, 3.4.8, 3.0.23, 1.1.1zj, 1.0.2zs

Recommended response

Check inventory. Check lockfiles and deployed manifests for OpenSSL/OpenSSL.
Review the reported fix. Update OpenSSL/OpenSSL to 4.0.3 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 29, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 29, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 29, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.