CVE-2026-42505
Medium
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.
SeverityMedium
CVSS5.3
Exploit probability—
ProductGo
PublishedJul 8, 2026
First seenJul 8, 2026
Weakness typeCWE-201CWE-201
How to fix
Update
- golang go1.25.12, 1.26.5 or later
- stdlib1.25.12, 1.26.5, 1.27.0-rc.2 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| golang go | 1.23.0 ≤ v < 1.25.12, 1.26.0 ≤ v < 1.26.5, 1.27 | 1.25.12, 1.26.5 |
| stdlibGo | v < 1.25.12, 1.26.0-0 ≤ v < 1.26.5, 1.27.0-0 ≤ v < 1.27.0-rc.2 | 1.25.12, 1.26.5, 1.27.0-rc.2 |
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