Amazon Linux 2027 Preview Security Advisory: ALAS2027-2026-239
Advisory Release Date: 2026-10-26 09:00 Pacific
Advisory Updated Date: 2026-10-26 09:00 Pacific
FAQs regarding Amazon Linux ALAS/CVE Severity
Package updates are available for Amazon Linux 2027 that fix the following vulnerabilities:
CVE-2026-93322:
A malicious frontend can submit an LLB definition that causes buildkitd
to panic and terminate, interrupting all builds running on that daemon.
CVE-2026-93321:
A malicious frontend can submit an LLB definition that causes buildkitd
to panic and terminate, interrupting all builds running on that daemon.
CVE-2026-93320:
BuildKit may be tricked into performing file actions with special file inodes where regular files are expected. Special files may block operations or, on rootful workers, allow unintended host device access.
CVE-2026-93319:
A malicious external BuildKit frontend can send requests using the internal API that can create conditions for a data race that can cause the BuildKit daemon to panic.
CVE-2026-93318:
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-2026-93317:
An unauthenticated attacker controlling a registry or OCI-layout blob source could provide blob contents that did not match the claimed digest. The resulting snapshot could be cached under that digest and reused by a later victim build, compromising build-input integrity.
CVE-2026-93316:
If BuildKit daemon is started with --cdi-disabled it can lead to daemon panic when builds try to use CDI devices. This can happen maliciously or by accident.
CVE-2026-78659:
When "Trailer" headers are sent by a client, the HTTP server internally uses the header values to populate the Request.Trailer map passed to the server handler. Because Request.Trailer is a map, each entry incurs memory overhead. For HTTP/2 servers, a malicious client can exploit this by sending a "Trailer" header that declares a large number of fields causing the server to allocate a disproportionate amount of memory while bypassing Server.MaxHeaderValueCount and Server.MaxHeaderBytes limits.
This exploit is not applicable for HTTP/1 servers, which do not support multiplexing a large number of requests over one TCP connection, and whose Server.MaxHeaderBytes are calculated differently.
Server.MaxHeaderValueCount and Server.MaxHeaderBytes limits are now applied towards the trailer fields declared in "Trailer" headers.
NOTE: https://www.openwall.com/lists/oss-security/2026/10/08/9
NOTE: https://github.com/golang/go/issues/81857
NOTE: Fixed by: https://github.com/golang/go/commit/cbb0fb8b51cba866018b8a0fb4b5458f16c5c80b (go1.27.2)
NOTE: Fixed by: https://github.com/golang/go/commit/6e049521882c944afc1e519a83971ec421dc2974 (go1.26.9)
Affected Packages:
runfinch-finch
Issue Correction:
Run dnf update runfinch-finch or dnf update --advisory ALAS2027-2026-239 to update your system.
aarch64:
runfinch-finch-1.19.0-1.amzn2027.0.2.aarch64
src:
runfinch-finch-1.19.0-1.amzn2027.0.2.src
x86_64:
runfinch-finch-1.19.0-1.amzn2027.0.2.x86_64