--- cve: "CVE-2026-54872" severity: "LOW" cvss: 3.7 epss: "0.3%" vendor: "OpenSSL" kev: false exploited: false published: "2026-09-29 16:17:08" tags: [cve, security, low] source: tsecurity.de CVE-Dossier exported: "2026-10-01T12:03:42+02:00" --- # CVE-2026-54872 > 3.7 LOW · 🧪 PoC ## Beschreibung 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. ## CNA-Record (Kanon, cvelistV5) - CNA: **openssl** - State: PUBLISHED - Stand: 2026-09-29 17:28:12 ## CISA-Anreicherung (vulnrichment/ADP) - CISA-SSVC (Coordinator, v2.0.3): - Exploitation: **none** - Automatable: **no** - Technical Impact: **partial** ## CVSS-Vektor ``` CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N ``` | Metrik | Wert | Bewertung | |---|---|---| | AV Angriffsvektor | Netzwerk | bad | | AC Komplexität | Hoch | good | | PR Privilegien | Keine | bad | | UI Interaktion | Keine | bad | | S Scope | Unverändert | good | | C Vertraulichkeit | Gering | warn | | I Integrität | Keine | good | | A Verfügbarkeit | Keine | good | ## Schwachstellen-Klasse - **CWE-208** — Observable Timing Discrepancy Two separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not. ## Angriffsmuster (CAPEC) - [CAPEC-462 — Cross-Domain Search Timing](https://capec.mitre.org/data/definitions/462.html) _(Severity: Medium)_ - [CAPEC-541 — Application Fingerprinting](https://capec.mitre.org/data/definitions/541.html) _(Severity: Low)_ - [CAPEC-580 — System Footprinting](https://capec.mitre.org/data/definitions/580.html) _(Severity: Low)_ ## ATT&CK-Techniken - [T1592.002 — Gather Victim Host Information: Software](https://attack.mitre.org/techniques/T1592/002/) - [T1082 — System Information Discovery](https://attack.mitre.org/techniques/T1082/) ## Patch verfügbar (OSV) - af1775b60dfa141a4ad762585052cabeb9f37e9e (Commit) - c8bd5a57108599ac650bbae77fcabe3109dab2e8 (Commit) ## BSI-Hinweise (deutsch) - [OpenSSL: Mehrere Schwachstellen](https://wid.cert-bund.de/portal/wid/sicherheitshinweis/WID-SEC-W-2026-3638) — _BSI-Einstufung: hoch_ Ein Angreifer kann mehrere Schwachstellen in OpenSSL ausnutzen, um Sicherheitsvorkehrungen zu umgehen, vertrauliche Informationen offenzulegen, Daten zu manipulieren und einen Denial-of-Service-Zustand zu verursachen. ## Referenzen - - - - - --- _Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-54872) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_