https://hackerone.com/p4p3r_hak" rel="nofollow">https://hackerone.com/p4p3r_hak) for reporting this issue. This is CVE-2026-42504 and Go issue https://go.dev/issue/79217. - net/textproto: arbitrary input are included in errors without any escaping When returning errors, functions in the net/textproto package would include its input as part of the error, without any escaping. Note that said input is often controlled by external parties when using this package naturally. For example, a net/http client uses ReadMIMEHeader when parsing the headers it receive from a server. As a result, an attacker could inject arbitrary content into the error. Practically, this can result in an attacker injecting misleading content, terminal control bytes, etc. into a victim's output or logs. This is CVE-2026-42507 and Go issue https://go.dev/issue/79346 - crypto/x509: split candidate hostname only once (*x509.Certificate).VerifyHostname previously called matchHostnames in a loop over all DNS Subject Alternative Name (SAN) entries. This caused strings.Split(host, ".") to execute repeatedly on the same input hostname. With a large DNS SAN list, verification costs scaled quadratically based on the number of SAN entries multiplied by the hostname's label count. Because x509.Verify validates hostnames before building the certificate chain, this overhead occurred even for untrusted certificates. Thanks to Jakub Ciolek (https://ciolek.dev) for reporting this issue. This is CVE-2026-27145 and https://go.dev/issue/79694. View the release notes for more information: https://go.dev/doc/devel/release#go1.26.4 Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>

Commits

Commits on Jun 3, 2026

update to go1.26.4