Summary
Package updates are available for Amazon Linux 2023 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-2026-42505: Handshakes which used Encrypted Client Hello could be de-anonymized by a passive network observer due to a disclosure of pre-shared key identities in the unencrypted client hello. CVE-2026-42504: Decoding a maliciously-crafted MIME header containing many invalid encoded-words can consume excessive CPU. CVE-2026-41579: When setting up the container rootfs, setupPtmx and setupDevSymlinks call os.Remove and os.Symlink with a filepath.Join string which allow an image with /dev as a symlink to trick runc into deleting files called ptmx on the host or creating a hardcoded set of symlinks with specific names and targets in an arbitrary pre-existing host directory. (from https://github.com/opencontainers/runc/security/advisories/GHSA-xjvp-4fhw-gc47) CVE-2026-39822: On Unix systems, opening a file in an os.Root improperly follows symlinks to locations outside of the Root when the final path component of the a path is a symbolic link and the path ends in /. For example, 'root.Open("symlink/")' will open "symlink" even when "symlink" is a symbolic link pointing outside of the root. 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 3
| Release | Package | Fixed in |
|---|---|---|
| Amazon Linux · 2023 | runc | 0:1.3.6-1.amzn2023.0.1 |
| Amazon Linux · 2023 | runc-debuginfo | 0:1.3.6-1.amzn2023.0.1 |
| Amazon Linux · 2023 | runc-debugsource | 0:1.3.6-1.amzn2023.0.1 |
Vulnerabilities 6
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High 7.8
Root escape via symlink plus trailing slash in os
On Unix systems, opening a file in an os.Root improperly follows symlinks to locations outside of the Root when the final path component of the a path is a symbolic link and the path ends in /. For example, 'root.Open("symlink/")' will open "symlink" even whe…
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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
Invoking Encrypted Client Hello privacy leak in crypto/tls
Handshakes which used Encrypted Client Hello could be de-anonymized by a passive network observer due to a disclosure of pre-shared key identities in the unencrypted client hello.
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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.
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Low 3.3
runc: Malicious image with /dev symlink can trigger limited host filesystem integrity violations
runc is a CLI tool for spawning and running containers according to the OCI specification. In versions prior to 1.3.6, 1.4.0-rc.1, 1.4.0-rc.12, 1.5.0-rc.1, and 1.5.0-rc.1, when setting up the container rootfs, setupPtmx and setupDevSymlinks call os.Remove and…
References
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-27145.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-39822.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-41579.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-42504.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-42505.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-42507.html