CVE-2026-56862Limit handshake messages we are willing to accept post-handshake in crypto/tls
Updated under an hour ago ()
Does this affect you?
It affects Go standard library crypto/tls. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.5 HIGH (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-770
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Go
- NVD analysis
- Awaiting Analysis
- Record last updated
- Aug 14, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Go standard library crypto/tls go_standard_library:crypto_tls (from the name) | before 1.25.13; from 1.26.0-0 before 1.26.6; 1.27.0-0 builds before 1.27.0-rc.3 | CNA record |
References
- https://go.dev/issue/80528
- https://go.dev/cl/804261
- https://groups.google.com/g/golang-announce/c/94pEornpRlI
- https://pkg.go.dev/vuln/GO-2026-6090
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.