Arch Linux Security Advisory ASA-201910-12
=========================================
Severity: Medium
Date    : 2019-10-21
CVE-ID  : CVE-2019-17596
Package : go
Type    : denial of service
Remote  : Yes
Link    : https://security.archlinux.org/AVG-1051

Summary
======
The package go before version 2:1.13.3-1 is vulnerable to denial of
service.

Resolution
=========
Upgrade to 2:1.13.3-1.

# pacman -Syu "go>=2:1.13.3-1"

The problem has been fixed upstream in version 1.13.3.

Workaround
=========
None.

Description
==========
Invalid DSA public keys can cause a panic in dsa.Verify. In particular,
using crypto/x509.Verify on a crafted X.509 certificate chain can lead
to a panic, even if the certificates don’t chain to a trusted root. The
chain can be delivered via a crypto/tls connection to a client, or to a
server that accepts and verifies client certificates. net/http clients
can be made to crash by an HTTPS server, while net/http servers that
accept client certificates will recover the panic and are unaffected.

Moreover, an application might crash invoking
crypto/x509.(*CertificateRequest) CheckSignature on an X.509
certificate request, parsing a golang.org/x/crypto/openpgp Entity, or
during a golang.org/x/crypto/otr conversation. Finally, a
golang.org/x/crypto/ssh client can panic due to a malformed host key,
while a server could panic if either PublicKeyCallback accepts a
malformed public key, or if IsUserAuthority accepts a certificate with
a malformed public key.

Impact
=====
A remote attacker can perform a denial of service attack by crafting a
malicious certificate chain.

References
=========
https://github.com/golang/go/issues/34960
https://security.archlinux.org/CVE-2019-17596