chore: update security updates to v1.26.4 [security]

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
go (source)	toolchain	patch	1.26.3 → 1.26.4

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Inefficient candidate hostname parsing in crypto/x509

BIT-golang-2026-27145 / CVE-2026-27145 / GO-2026-5037

More information

Details

(*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.

Severity

Unknown

References

• https://go.dev/cl/783621
• https://go.dev/issue/79694
• https://groups.google.com/g/golang-announce/c/tKs3rmcBcKw

This data is provided by OSV and the Go Vulnerability Database (CC-BY 4.0).

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Quadratic complexity in WordDecoder.DecodeHeader in mime

BIT-golang-2026-42504 / CVE-2026-42504 / GO-2026-5038

More information

Details

Decoding a maliciously-crafted MIME header containing many invalid encoded-words can consume excessive CPU.

Severity

Unknown

References

• https://go.dev/issue/79217
• https://go.dev/cl/774481
• https://groups.google.com/g/golang-announce/c/tKs3rmcBcKw

This data is provided by OSV and the Go Vulnerability Database (CC-BY 4.0).

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Arbitrary inputs are included in errors without any escaping in net/textproto

BIT-golang-2026-42507 / CVE-2026-42507 / GO-2026-5039

More information

Details

When returning errors, functions in the net/textproto package would include its input as part of the error. This might allow an attacker to inject misleading content to errors that are printed or logged.

Severity

Unknown

References

• https://go.dev/issue/79346
• https://go.dev/cl/777060
• https://groups.google.com/g/golang-announce/c/tKs3rmcBcKw

This data is provided by OSV and the Go Vulnerability Database (CC-BY 4.0).

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Release Notes

golang/go (go)

v1.26.4

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