CVE-2026-123612

medium

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.

References

https://www.vulncheck.com/advisories/rustls-0.23.44-and-0.23.45-ech-rejection-application-data-disclosure

https://github.com/rustls/rustls/security/advisories/GHSA-vp88-798v-h67f

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-119371

Details

Source: Mitre, NVD

Published: 2026-11-08

Updated: 2026-11-08

Risk Information

CVSS v2

Base Score: 1.4

Vector: CVSS2#AV:L/AC:L/Au:M/C:P/I:N/A:N

Severity: Low

CVSS v3

Base Score: 2.3

Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N

Severity: Low

CVSS v4

Base 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

Severity: Medium

EPSS

EPSS: 0.0011