| id: GO-2026-5856 |
| modules: |
| - module: std |
| versions: |
| - fixed: 1.25.12 |
| - introduced: 1.26.0-0 |
| - fixed: 1.26.5 |
| - introduced: 1.27.0-0 |
| - fixed: 1.27.0-rc.2 |
| vulnerable_at: 1.27.0-rc.1 |
| packages: |
| - package: crypto/tls |
| symbols: |
| - clientHelloMsg.marshalMsg |
| derived_symbols: |
| - Conn.Handshake |
| - Conn.HandshakeContext |
| - Conn.Read |
| - Conn.Write |
| - Dial |
| - DialWithDialer |
| - Dialer.Dial |
| - Dialer.DialContext |
| - QUICConn.HandleData |
| - QUICConn.SendSessionTicket |
| - QUICConn.Start |
| summary: Invoking Encrypted Client Hello privacy leak in crypto/tls |
| description: |- |
| Handshakes which used Encrypted Client Hello could be de-anonymized by a passive |
| network observer due to a disclosure of pre-shared key identities in the |
| unencrypted client hello. |
| credits: |
| - Coia Prant (github.com/rbqvq) |
| references: |
| - fix: https://go.dev/cl/775960 |
| - report: https://go.dev/issue/79282 |
| - web: https://groups.google.com/g/golang-announce/c/OrmQE_Yp5Sc |
| cve_metadata: |
| id: CVE-2026-42505 |
| cwe: 'CWE-201: Insertion of Sensitive Information Into Sent Data' |
| source: |
| id: go-security-team |
| review_status: REVIEWED |
