ALAS2023-2026-1901

References: CVE-2026-27145  CVE-2026-41567  CVE-2026-42504  CVE-2026-42507 
FAQs regarding Amazon Linux ALAS/CVE Severity

Issue Overview:

(*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. (CVE-2026-27145)

Moby is an open source container framework. In versions prior to 29.5.1 and in moby/moby v2 prior to v2.0.0-beta.14, when a compressed archive is uploaded to a container via `PUT /containers/{id}/archive` or piped through `docker cp -`, the daemon resolves decompression binaries (such as `xz` or `unpigz`) from the container's filesystem rather than the host's due to incorrect ordering of operations. A malicious container image containing a trojanized decompression binary can achieve arbitrary code execution with full daemon privileges, including host root UID and unrestricted capabilities, when a user uploads a compressed (xz or gzip) archive into that container. This issue is fixed in Docker Engine 29.5.1 and moby/moby v2.0.0-beta.14. Workarounds include only running containers from trusted images, using authorization plugins to restrict access to the `PUT /containers/{id}/archive` endpoint, and avoiding piping compressed archives into containers created from untrusted images (CVE-2026-41567)

Decoding a maliciously-crafted MIME header containing many invalid encoded-words can consume excessive CPU. (CVE-2026-42504)

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-2026-42507)

Issue Correction:
Run dnf update docker --releasever 2023.12.20260706 or dnf update --advisory ALAS2023-2026-1901 --releasever 2023.12.20260706 to update your system.
More information on how to update your system can be found on this page: Amazon Linux 2023 documentation

New Packages:

aarch64:
    docker-debuginfo-25.0.16-1.amzn2023.0.3.aarch64
    docker-25.0.16-1.amzn2023.0.3.aarch64
    docker-debugsource-25.0.16-1.amzn2023.0.3.aarch64

src:
    docker-25.0.16-1.amzn2023.0.3.src

x86_64:
    docker-debuginfo-25.0.16-1.amzn2023.0.3.x86_64
    docker-25.0.16-1.amzn2023.0.3.x86_64
    docker-debugsource-25.0.16-1.amzn2023.0.3.x86_64