Red Hat alert RHSA-2026:70640-01 (buildah)

An update for buildah is now available for Red Hat Enterprise Linux 9.

Red Hat Product Security has rated this update as having a security impact of
Important. A Common Vulnerability Scoring System (CVSS) base score, which
gives a detailed severity rating, is available for each vulnerability from
the CVE link(s) in the References section.

The buildah package provides a tool for facilitating building OCI container
images. Among other things, buildah enables you to: Create a working
container, either from scratch or using an image as a starting point; Create
an image, either from a working container or using the instructions in a
Dockerfile; Build both Docker and OCI images.

Security Fix(es):

* buildah: Go net/http: Unencrypted HTTP/2 connections vulnerable to Denial
of Service (CVE-2026-56853)

* buildah: Go html/template: Cross-Site Scripting via pathological input
(CVE-2026-56858)

* buildah: Go encoding/asn1: Denial of Service via excessive recursion in
Unmarshal (CVE-2026-33818)

* buildah: golang net/url: Denial of Service from quadratic complexity in
path resolution (CVE-2026-56860)

* buildah: Golang crypto/tls: Denial of Service via indefinite KeyUpdate
messages (CVE-2026-56862)

For more details about the security issue(s), including the impact, a CVSS
score, acknowledgments, and other related information, refer to the CVE
page(s) listed in the References section.

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Original: https://access.redhat.com/security/data/csaf/v2/advisories/2026/rhsa-2026_70640.json