What's Changed

• [release-1.21] Replace registry.centos.org by @cevich in https://github.com/containers/buildah/pull/4854
• [release-1.21] conformance test: ignore file type bits when comparing layers by @cevich in https://github.com/containers/buildah/pull/5265
• [release-1.21] conformance tests: don't break on trailing zeroes in layer blobs by @openshift-cherrypick-robot in https://github.com/containers/buildah/pull/5509
• [release-1.21] tests/conformance/testdata/Dockerfile.add:... by @openshift-cherrypick-robot in https://github.com/containers/buildah/pull/6054
• [release-1.21] Bump runc to v1.2.9 - CVE-2025-52881 by @dashea in https://github.com/containers/buildah/pull/6522

Full Changelog: https://github.com/containers/buildah/compare/v1.21.5...v1.21.6