CVE-2026-56862
High
Description
Handshake messages, such as KeyUpdate, are always considered as state-advancing, regardless of whether a handshake has been completed or not. As a result, a malicious client can keep sending KeyUpdate messages to force the server to keep performing key derivation operations indefinitely.
SeverityHigh
CVSS7.5
Exploit probability—
ProductStdlib
PublishedAug 13, 2026
First seenAug 13, 2026
Weakness typeCWE-770Allocation of resources without limits
How to fix
Update
- stdlib1.25.13, 1.26.6, 1.27.0-rc.3 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| stdlibGo | v < 1.25.13, 1.26.0-0 ≤ v < 1.26.6, 1.27.0-0 ≤ v < 1.27.0-rc.3 | 1.25.13, 1.26.6, 1.27.0-rc.3 |
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