[LOW] Patch expat for CVE-2026-41080 CVE-2026-45186

[Ratiranjan5]

Merge Checklist

All boxes should be checked before merging the PR (just tick any boxes which don't apply to this PR)

• The toolchain has been rebuilt successfully (or no changes were made to it)
• The toolchain/worker package manifests are up-to-date
• Any updated packages successfully build (or no packages were changed)
• Packages depending on static components modified in this PR (Golang, *-static subpackages, etc.) have had their Release tag incremented.
• Package tests (%check section) have been verified with RUN_CHECK=y for existing SPEC files, or added to new SPEC files
• All package sources are available
• cgmanifest files are up-to-date and sorted (./cgmanifest.json, ./toolkit/scripts/toolchain/cgmanifest.json, .github/workflows/cgmanifest.json)
• LICENSE-MAP files are up-to-date (./LICENSES-AND-NOTICES/SPECS/data/licenses.json, ./LICENSES-AND-NOTICES/SPECS/LICENSES-MAP.md, ./LICENSES-AND-NOTICES/SPECS/LICENSE-EXCEPTIONS.PHOTON)
• All source files have up-to-date hashes in the *.signatures.json files
• sudo make go-tidy-all and sudo make go-test-coverage pass
• Documentation has been updated to match any changes to the build system
• Ready to merge

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Summary

What does the PR accomplish, why was it needed?
Patch expat for CVE-2026-41080 CVE-2026-45186
Patch modified: Yes

• The expat package (version 2.6.4) is affected by CVE-2026-41080 and CVE-2026-45186, as the vulnerability impacts versions earlier than 2.8.0.
  CVE-2026-41080:
• This issue is caused by insufficient entropy used for hash salt generation, which can allow hash-flooding attacks via crafted XML input leading to denial-of-service.
• The upstream fix improves hash flooding protection by increasing entropy from 4–8 bytes to 16 bytes, leveraging full SipHash capabilities and enhancing randomness in hash salt generation.
• The patch has been backported manually by applying only the required changes to source package (xmlparse.c, internal.h, and expat.h).
• Non-essential upstream changes (documentation updates, test additions, CI-related files, and symbol export files) have been excluded as they are not required for the CVE fix. Example: doc/reference.html, data/exported-symbols-unversioned.txt, exported-symbols-versioned-default.txt, lib/libexpat.map.in, tests/basic_tests.c and Changes etc.
• Replaced recursive parent parser delegation with using getRootParserOf() helper that fixes undeclared variable error and improves code consistency with upstream implementation.
• As in upstream, added platform-specific guard to skip PID entropy in WASI environments.

CVE-2026-45186:

• Only the minimal necessary changes in the core library (xmlparse.c) have been included to address the CVE, while test and documentation changes have been intentionally excluded like the changes in tests/basic_tests.c, tests/handlers.c, tests/handlers.h and Changes.

• Upstream Patch reference for CVE-2026-41080: https://patch-diff.githubusercontent.com/raw/libexpat/libexpat/pull/1183.patch

• Upstream Patch reference for CVE-2026-45186: https://patch-diff.githubusercontent.com/raw/libexpat/libexpat/pull/1216.patch

Change Log

• new file: SPECS/expat/CVE-2026-41080.patch
• modified: SPECS/expat/expat.spec
• modified: toolkit/resources/manifests/package/pkggen_core_aarch64.txt
• modified: toolkit/resources/manifests/package/pkggen_core_x86_64.txt
• modified: toolkit/resources/manifests/package/toolchain_aarch64.txt
• modified: toolkit/resources/manifests/package/toolchain_x86_64.txt

Does this affect the toolchain?

YES

Associated issues

• #xxxx

Links to CVEs

• https://nvd.nist.gov/vuln/detail/CVE-2026-41080

Test Methodology

• Local build was successful.

• Patch applies cleanly.

• Installation:

• Uninstallation:

[Ratiranjan5]

buddy build: https://dev.azure.com/mariner-org/mariner/_build/results?buildId=1128694&view=results

[Ratiranjan5]

buddy build: https://dev.azure.com/mariner-org/mariner/_build/results?buildId=1128694&view=results

buddy build has passed.