CVE-2026-56862
Limit handshake messages we are willing to accept post-handshake in crypto/tls
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.
INFO
Published Date :
Aug. 13, 2026, 10:17 p.m.
Last Modified :
Aug. 13, 2026, 10:17 p.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-56862
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Limit the rate of KeyUpdate messages from clients.
- Implement server-side logic to track key derivation attempts.
- Reject excessive KeyUpdate messages from untrusted clients.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-56862.
| URL | Resource |
|---|---|
| https://go.dev/cl/804261 | |
| https://go.dev/issue/80528 | |
| https://groups.google.com/g/golang-announce/c/94pEornpRlI | |
| https://pkg.go.dev/vuln/GO-2026-6090 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-56862 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-56862
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-56862 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-56862 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Aug. 13, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Go standard library', 'product': 'crypto/tls', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '1.25.13', 'versionType': 'semver'}, {'status': 'affected', 'version': '1.26.0-0', 'lessThan': '1.26.6', 'versionType': 'semver'}, {'status': 'affected', 'version': '1.27.0-0', 'lessThan': '1.27.0-rc.3', 'versionType': 'semver'}], 'packageName': 'crypto/tls', 'collectionURL': 'https://pkg.go.dev', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': 'Conn.readRecordOrCCS'}, {'name': 'Conn.Handshake'}, {'name': 'Conn.HandshakeContext'}, {'name': 'Conn.Read'}, {'name': 'Conn.Write'}, {'name': 'Dial'}, {'name': 'DialWithDialer'}, {'name': 'Dialer.Dial'}, {'name': 'Dialer.DialContext'}, {'name': 'QUICConn.HandleData'}, {'name': 'QUICConn.Start'}]}] Added 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. Added Reference https://go.dev/cl/804261 Added Reference https://go.dev/issue/80528 Added Reference https://groups.google.com/g/golang-announce/c/94pEornpRlI Added Reference https://pkg.go.dev/vuln/GO-2026-6090