Summary
Package updates are available for Amazon Linux 2 that fix the following vulnerabilities: CVE-2026-42507: 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. CVE-2026-42504: Decoding a maliciously-crafted MIME header containing many invalid encoded-words can consume excessive CPU. CVE-2026-27145: (*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.
Fixed packages 2
| Release | Package | Fixed in |
|---|---|---|
| Amazon Linux · 2 | nerdctl | 0:2.2.2-1.amzn2.0.4 |
| Amazon Linux · 2 | nerdctl-debuginfo | 0:2.2.2-1.amzn2.0.4 |
Vulnerabilities 3
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High 7.5
Quadratic complexity in WordDecoder.DecodeHeader in mime
Decoding a maliciously-crafted MIME header containing many invalid encoded-words can consume excessive CPU.
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Medium 6.5CVE-2026-27145 Public exploit
Inefficient candidate hostname parsing in crypto/x509
(*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 c…
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Medium 5.3
Arbitrary inputs are included in errors without any escaping in net/textproto
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.