[AutoPR- Security] Patch libssh2 for CVE-2026-55199, CVE-2025-15661 [MEDIUM]

[azurelinux-security]

Auto Patch libssh2 for CVE-2026-55199, CVE-2025-15661.

Autosec pipeline run -> https://dev.azure.com/mariner-org/mariner/_build/results?buildId=1147853&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

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Summary

What does the PR accomplish, why was it needed?

• Auto Patch libssh2 for CVE-2026-55199 (MEDIUM), CVE-2025-15661 (MEDIUM).

Change Log

• CVE-2026-55199
• CVE-2025-15661

Does this affect the toolchain?

YES/NO

Associated issues

• N/A

Links to CVEs

• https://nvd.nist.gov/vuln/detail/CVE-2026-55199
• https://nvd.nist.gov/vuln/detail/CVE-2025-15661

Test Methodology

• Pipeline build id: Buddy Build URL

[AkarshHCL]

1. Fixed the failing buddy build due to macro-LIBSSH2_UNCONST , removed this macro, it does not exist and data variable is already unsigned char* .
2. Buddy build after the fix-https://dev.azure.com/mariner-org/mariner/_build/results?buildId=1148879&view=results
3. patches are getting applied cleanly-

[AkarshHCL]

Our patch is different from upstream as our source code is slightly different. Our AI backport added necessary changes with the following relevance:

1. Type Consistency (unsigned int → uint32_t)

   • SSH protocol uses 32-bit types
   • Prevents platform-dependent integer issues
   • Not removed from upstream - Azure Linux adaptation

2. Packet Length Refactoring (Separated initialization)

   • Improves clarity and enables bounds checking
   • Type safety (ssize_t → uint32_t)
   • Not removed from upstream - Code quality improvement

3. Core Security Variables (5 new variables)

   • struct string_buf buf, lk_target, packet_type, tmp_u32, lk_len
   • Same as upstream - Implements CVE-2025-15661 fix