CVE-2026-34873
criticalAn issue was discovered in Mbed TLS 3.5.0 through 4.0.0.
Vendor / product: Trustedfirmware — mbed tls
An issue was discovered in Mbed TLS 3.5.0 through 4.0.0. Client impersonation can occur while resuming a TLS 1.3 session.
CVSS
9.1
9.1 (CVSS v3.1)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Severity source: NVD CVSS v3.1 (134c704f-9b21-4f2e-91b3-4a467353bcc0)
Timeline (UTC)
Published: 2026-04-01 21:17
Modified: 2026-11-11 23:10
NVD status: Analyzed
Last synced 3 hours ago
Verified against the source API 2026-11-11 23:12 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).
Affected products
trustedfirmware / mbed_tls ≥3.5.0 <3.6.6, ≥4.0.0 <4.1.0
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
Vendor advisory: https://mbed-tls.readthedocs.io/en/latest/security-advisories/
References
Data sources
NVD CVE API 2.0 — fetched 2026-11-11 23:12 UTC · record ↗