Arch Linux Security Advisory ASA-202107-42 ========================================== Severity: Low Date : 2021-07-20 CVE-ID : CVE-2021-34558 Package : go Type : denial of service Remote : Yes Link : https://security.archlinux.org/AVG-2147 Summary ======= The package go before version 2:1.16.6-1 is vulnerable to denial of service. Resolution ========== Upgrade to 2:1.16.6-1. # pacman -Syu "go>=2:1.16.6-1" The problem has been fixed upstream in version 1.16.6. Workaround ========== Clients that disable all TLS_RSA cipher suites (that is, TLS 1.0–1.2 cipher suites without ECDHE), as well as TLS 1.3-only clients, are unaffected. Description =========== A security issue has been found in Go before version 1.16.6. crypto/tls clients can panic when provided a certificate of the wrong type for the negotiated parameters. net/http clients performing HTTPS requests are also affected. The panic can be triggered by an attacker in a privileged network position without access to the server certificate's private key, as long as a trusted ECDSA or Ed25519 certificate for the server exists (or can be issued), or the client is configured with Config.InsecureSkipVerify. Clients that disable all TLS_RSA cipher suites (that is, TLS 1.0–1.2 cipher suites without ECDHE), as well as TLS 1.3-only clients, are unaffected. Impact ====== A man-in-the-middle attacker able to intercept a TLS negotiation could crash a TLS client by injecting a crafted invalid certificate. References ========== https://groups.google.com/g/golang-announce/c/n9FxMelZGAQ/m/4ZhvTx0dAQAJ https://github.com/golang/go/issues/47143 https://github.com/golang/go/commit/58bc454a11d4b3dbc03f44dfcabb9068a9c076f4 https://security.archlinux.org/CVE-2021-34558