CVE-2026-54872
Vulnérabilité faible dans OpenSSL (OpenSSL)
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.
Gravité et risque d'exploitation
CVE-2026-54872 obtient un score CVSS de 3.7/10, soit une gravité faible. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.26 %, ce qui la place devant 16.9 % des CVE référencées.
Que faire ?
- Vérifiez si OpenSSL (versions <3.5.9, <1.1.1zj, <3.0.23, 3.6.0, 3.0.0, 4.0.0, 1.1.1, 1.0.2, 3.5.0, <1.0.2zs, <4.0.3, <3.4.8, 3.4.0, <3.6.5) est présent sur votre parc.
- Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
- À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
- Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.
Références
- https://openssl-library.org/news/secadv/20260929.txt
- https://github.com/openssl/openssl/commit/8166827a78aad164a07aa86dea2b425403ced471
- https://github.com/openssl/openssl/commit/1a5bee8dc57430a2be69cd1ffe7fec6a62f4f179
- https://github.com/openssl/openssl/commit/3f7e1363dccec6f7732bb9e9fa471bb6e4aa68cb
- https://github.com/openssl/openssl/commit/7d83bc7764999dfd91b83b4f0815b45390422afd
