fix(deps): upgrade mcp to 1.28.1 for 3 High-severity CVEs

[IlonaShishov]

Summary

Upgrades mcp (MCP Python SDK) from 1.27.1 → 1.28.1, fixing three High-severity CVEs:

CVE	CVSS	Fixed in	Description
CVE-2026-52870	7.6 High	v1.27.2	Experimental task handlers allow any client to list, read, and cancel other clients' tasks (no session-ownership check)
CVE-2026-52869	7.1 High	v1.27.2	SSE/Streamable HTTP transports route requests by session ID alone without verifying the bearer token matches the session creator
CVE-2026-59950	7.6 High	v1.28.1	Deprecated WebSocket transport accepts handshakes with no Host/Origin validation

Impact on this project

All three CVEs have low direct risk to this project:

• CVE-2026-52870 — Only affects servers calling server.experimental.enable_tasks(). This project uses mcp as a client, not a server with experimental tasks.
• CVE-2026-52869 — Only affects MCP servers using HTTP transports with built-in bearer-token auth. Same reason — we are an MCP client.
• CVE-2026-59950 — Only affects the deprecated WebSocket server transport. This project does not expose a WebSocket MCP server.

Despite low direct exposure, upgrading is the right call — it's a minimal change, all three CVEs are High severity, and it keeps the dependency current and audit-clean.

Changes

• pyproject.toml: pin mcp==1.28.1 (was mcp>=1.0.0)
• requirements-agent.txt: regenerated lock file (also picks up idna 3.17 → 3.18 as a transitive dep bump)

Supersedes #333 (Konflux MintMaker's auto-generated PR for the same upgrade).

Test plan

• make lint — all checks passed
• make test — 490 passed
• No breaking changes: project only imports mcp.StdioServerParameters, which is stable across 1.27→1.28

🤖 Generated with Claude Code

[yuvalk]

seems like 3 irrelevant CVEs, so why are we upgrading?

[IlonaShishov]

seems like 3 irrelevant CVEs, so why are we upgrading?

@yuvalk I see a benefit in staying ahead of all package CVEs, at least, if not the latest version, especially since its a minimal change.
Also, our CI pipeline vulnerability scan will fails on these 3:

● Bash(git checkout main && source .venv/bin/activate && make audit)
  ⎿  Error: Exit code 2
     Switched to branch 'main'
     Your branch is up to date with 'origin/main'.
     Scanning dependencies for known vulnerabilities...
     uv tool run pip-audit --no-deps --disable-pip -r requirements-agent.txt
     Downloading pip (1.7MiB)
     Downloading pygments (1.2MiB)
      Downloaded pygments
      Downloaded pip
     Installed 28 packages in 208ms
     WARNING:pip_audit._cli:--no-deps is supported, but users are encouraged to fully hash their pinned dependencies
     WARNING:pip_audit._cli:Consider using a tool like `pip-compile`: https://pip-tools.readthedocs.io/en/latest/#using-hashes
     Found 3 known vulnerabilities in 1 package
     Name Version ID              Fix Versions
     ---- ------- --------------- ------------
     mcp  1.27.1  PYSEC-2026-3482 1.27.2
     mcp  1.27.1  PYSEC-2026-3483 1.28.1
     mcp  1.27.1  PYSEC-2026-3481 1.27.2
     make: *** [Makefile:118: audit] Error 1

[luis5tb]

lets get those in to make the gate green