[AutoPR- Security] Patch python-pip for CVE-2026-13346 [MEDIUM]

[azurelinux-security]

Auto Patch python-pip for CVE-2026-13346.

Autosec pipeline run -> https://dev.azure.com/mariner-org/mariner/_build/results?buildId=1174137&view=results

CVE-2026-13346 : Single Patch Backporter Pipeline Run -> https://dev.azure.com/mariner-org/mariner/_build/results?buildId=1174140&view=results

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

---

Summary

What does the PR accomplish, why was it needed?

• Auto Patch python-pip for CVE-2026-13346 (MEDIUM).

Change Log

• CVE-2026-13346

Does this affect the toolchain?

YES/NO

Associated issues

• N/A

Links to CVEs

• https://nvd.nist.gov/vuln/detail/CVE-2026-13346

Test Methodology

• Pipeline build id: Buddy Build URL

[azure-pipelines]

Azure Pipelines:
There may be pipelines that require an authorized user to comment /azp run to run.

[v-swapsahu]

Patch analysis:

CVE-2026-13346:
Backported: Yes

The python-pip patch matches the upstream security fix with a minor adaptation for pip 24.2.

• Removes the second URL decoding in Link.filename.
• Prevents doubly encoded separators from enabling path traversal.
• Validates filenames as safe, single path components.
• Uses join_within_directory() for all affected download and preparation paths.

Minor backport modification:
pip 24.2 has separate Downloader and BatchDownloader implementations, so both paths were updated. This functionally matches the upstream fix.

The patch applies cleanly, and the modified Python modules compile successfully. No security-relevant upstream changes were omitted.

Buddy Build - Pipelines - Run PR-18290+python-pip+unknown has been triggered and it has passed.