CVE-2026-123612

rustls 0.23.44 and 0.23.45 ECH Rejection Application Data Disclosure

Published Nov 8, 2026 CVSS 4.0 · 4.6 Medium EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Description 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.
Title rustls 0.23.44 and 0.23.45 ECH Rejection Application Data Disclosure
First Time appeared Rustls Project
Rustls Project rustls
Weaknesses CWE-696
CPEs cpe:2.3:a:rustls_project:rustls:*:*:*:*:*:*:*:*
Vendors & Products Rustls Project
Rustls Project rustls
References
Metrics cvssV3_1

{'score': 2.3, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N'}

cvssV4_0

{'score': 4.6, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Nov 12, 2026, 1:40 PM
Reserved
Nov 6, 2026, 1:02 AM
Status
Awaiting Analysis
Published
Nov 8, 2026, 2:16 AM
Modified
Nov 12, 2026, 9:30 PM