Summary
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:](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.
Fixed packages 2
| Release | Package | Fixed in |
|---|---|---|
| AlmaLinux · 9 | buildah | 2:1.43.3-2.el9_8 |
| AlmaLinux · 9 | buildah-tests | 2:1.43.3-2.el9_8 |
Vulnerabilities 8
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High 7.5
Enforce maximum recursion depth in encoding/asn1
Enforce a recursion limit in Unmarshal to prevent stack exhaustion when parsing deeply-nested, recursive structures.
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High 7.5
Apply ReadHeaderTimeout when doing unencrypted HTTP/2 check in net/http
When a server is configured to support unencrypted HTTP/2, it reads a few bytes from each new connection to see if they contain the HTTP/2 client preface. ReadHeaderTimeout is unexpectedly not being applied when doing this.
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High 7.5
Prevent DoS on deadlocked established channel in golang.org/x/crypto/ssh
Previously, after a channel has been established, a malicious peer could send crafted messages that would deadlock the entire connection. Now, we handle all RFC 4254 channel messages; global requests are handled explicitly. Then, treat all other messages as a…
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High 7.5
Limit handshake messages we are willing to accept post-handshake in crypto/tls
Handshake messages, such as KeyUpdate, are always considered as state-advancing, regardless of whether a handshake has been completed or not. As a result, a malicious client can keep sending KeyUpdate messages to force the server to keep performing key deriva…
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Medium 6.9
Malicious client can bypass destination directory validation on local sources upload
A custom client can produce such an upload request to the BuildKit daemon that files can escape from the BuildKit-controlled state directory. The client needs to have valid permissions to access the BuildKit control API to issue builds, e.g., bypass authentic…
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Medium 6.1
Fix Javascript regexp context tracking in html/template
Previously, pathological inputs could close an unescaped '/' early, allowing for attack-controlled data to inject arbitrary content, potentially leading to XSS.
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Medium 5.9
Avoid quadratic complexity in resolvePath in net/url
Previously, resolving relative paths containing parent directory ('..') segments performed string conversions and buffer rewrites on each step, resulting in quadratic time complexity and high memory allocation overhead. Now, path resolution operates on a byte…
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Medium 5.5
Podman: arbitrary file write when importing oci archive
A flaw was found in Podman. If an attacker can pass a crafted tar archive to the `podman load` command, they can create files on the host machine with the privileges of the user running Podman.
References
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report
https://access.redhat.com/security/cve/CVE-2025-11395
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report
https://access.redhat.com/security/cve/CVE-2026-15789
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report
https://access.redhat.com/security/cve/CVE-2026-33818
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report
https://access.redhat.com/security/cve/CVE-2026-56853
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report
https://access.redhat.com/security/cve/CVE-2026-56855
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report
https://access.redhat.com/security/cve/CVE-2026-56858
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report
https://access.redhat.com/security/cve/CVE-2026-56860
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report
https://access.redhat.com/security/cve/CVE-2026-56862
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report
https://bugzilla.redhat.com/2515815
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report
https://bugzilla.redhat.com/2515820
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report
https://bugzilla.redhat.com/2515827
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report
https://bugzilla.redhat.com/2515838
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report
https://bugzilla.redhat.com/2515839
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advisory
https://errata.almalinux.org/9/ALSA-2026-70640.html