ALAS2023-2026-3391

References: CVE-2026-71482  CVE-2026-78661  CVE-2026-93318  CVE-2026-97045 
FAQs regarding Amazon Linux ALAS/CVE Severity

Issue Overview:

eStargz layer decoder in the estartgz package contains a vulnerability that an input containing a cyclic hardlink crashes the process with Go's unrecoverable stack overflow error. Stargz Snapshotter with the default configuration relies on that function so pulling an eStargz image containing a muliciously crafted layer with a cyclic hardlink crashes the Stargz Snapshotter process. (CVE-2026-71482)

When coalescing adjacent text nodes in addText and fosterParent, appending to an existing TextNode's Data via string concatenation (n.Data += text) reallocated and copied the accumulated string on every token. Inputs containing many short text runs separated by ignored end tags (such as "a</x>") caused O(n^2) allocations and byte copies. Accumulate coalesced text in per-node byte slices during parsing and materialize Data strings once at the end of parse. (CVE-2026-78661)

A malicious image can advertise DiffIDs from another image while containing different layer contents. In affected versions, BuildKit could use the advertised DiffIDs to derive cache and snapshot identity without validating that they matched the actual layer contents.

If a BuildKit daemon with shared or persistent cache first processes such a malicious image, a later build using the victim image may mount the attacker-controlled layer contents as the base image. This can allow code from the malicious image to run in the victim build, for example by replacing a commonly executed path such as /bin/sh. The attacker-controlled code may read build secrets mounted into the build, access other build resources, alter output artifacts, or hang the build.

The issue affects both regular snapshotters and lazy-pulling snapshotters such as stargz. (CVE-2026-93318)

In childTextNodesAreLiteral, walking up the tree previously stopped at the nearest foreign ancestor once an HTML integration point was found. However, that integration point may itself be a descendant of an element that was foster-parented into a foreign namespace (such as <mglyph> or <malignmark> fostered under <mtext>), causing a parser to resolve the subtree in a different foreign namespace upon re-parsing the rendered output. Continue walking the full ancestor chain and verify that every transition from a non-empty namespace occurs at an HTML integration point before emitting literal text. (CVE-2026-97045)

Issue Correction:
Run dnf update docker --releasever 2023.12.20261109 or dnf update --advisory ALAS2023-2026-3391 --releasever 2023.12.20261109 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-25.0.18-1.amzn2023.0.3.aarch64
    docker-25.0.18-1.amzn2023.0.3.aarch64
    docker-debugsource-25.0.18-1.amzn2023.0.3.aarch64

src:
    docker-25.0.18-1.amzn2023.0.3.src

x86_64:
    docker-25.0.18-1.amzn2023.0.3.x86_64
    docker-debugsource-25.0.18-1.amzn2023.0.3.x86_64
    docker-debuginfo-25.0.18-1.amzn2023.0.3.x86_64