Vulnerability in Rustls
CVE-2026-123612
rustls 0.23.44 and 0.23.45 contain an information disclosure vulnerability that sends application data buffered before the handshake completes to the client-facing server when Encrypted Client Hello is rejected. Because start_traffic() queues plaintext from ClientConnection::writer() before sending the ech_required alert, the authenticated public_name server receives data intended for the inner server.
Published .
CVSS v3 metric
CVSS v3 base score 2.3 (Low). Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/rustls/rustls/security/advisories/GHSA-vp88-798v-h67f (vendor-advisory)
- www.vulncheck.com/advisories/rustls-0.23.44-and-0.23.45-ech-rejection-applicati… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-123612?
- CVE-2026-123612 is a low-severity vulnerability in Rustls, classified under CWE-696. CVSS score: 2.3/10. Published 2026-11-08.
- How severe is CVE-2026-123612?
- Low severity. CVSS v3 base score is 2.3 out of 10.