CVE-2026-56862: high-severity vulnerability in Go standard library crypto/tls
Limit handshake messages we are willing to accept post-handshake in crypto/tls
Published · Updated
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 0.6%
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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
Go standard library · crypto/tlsRelated CVEs — Go standard library crypto/tls
In the same product, most dangerous first.
CVE-2023-29409—Large RSA keys can cause high CPU usage in crypto/tlsEPSS 1.6%CVE-2023-39322—Memory exhaustion in QUIC connection handling in crypto/tlsEPSS 1.3%CVE-2023-39321—Panic when processing post-handshake message on QUIC connections in crypto/tlsEPSS 1.3%CVE-2023-45287—Before Go 1.20, the RSA based key exchange methods in crypto/tls may exhibit a timing side channelEPSS 1.3%CVE-2022-30629LOWSession tickets lack random ticket_age_add in crypto/tlsEPSS 1.2%CVE-2022-41724—Panic on large handshake records in crypto/tlsEPSS 1.1%