chore(deps): resolve backend dependency CVEs (pysaml2 fork, cryptography, twisted, pydantic-ai)

[silvestrid]

What

Resolves all fixable Dependabot alerts on the backend (4 high, 3 low, 3 medium).

1. pysaml2 fork (2ec1971f)

pysaml2==7.5.4 caps pyopenssl<24.3.0, which blocked upgrading cryptography past the CVE-2026-26007 fix. Upstream fix exists but is unreleased (IdentityPython/pysaml2#1021), so we cherry-picked it into baserow/pysaml2 (fork PR #1, tag v7.5.4+deps-upgrade) and consume it via [tool.uv.sources] pinned to the immutable merge-commit SHA (a tag can be force-moved; the SHA cannot). Drop the source and return to PyPI once upstream releases the fix.

git is added to the Dockerfile builder-prod-base and dev stages — uv needs the git CLI to fetch git-sourced dependencies and the python-slim base image doesn't ship it.

2. Remaining CVE upgrades (dbf1effa)

Package	Before → After	Fixes
cryptography	43.0.3 → 49.0.0	2 high + 2 low (incl. CVE-2026-26007)
pyopenssl	24.2.1 → 26.3.0	1 high + 1 low
twisted	25.5.0 → 26.4.0	1 high (DNS compression DoS)
pydantic-ai-slim	1.77.0 → 1.102.0	2 medium (SSRF bypasses); needs boto3 ≥ 1.42.63
pydantic-settings	2.12.0 → 2.14.2	1 medium
django / daphne	5.2.15 / 4.2.2	security patches

pydantic-ai 1.102 turned StreamedResponse._parts_manager into a cached_property (plus new _finished/_cancelled class-default fields), which shadowed __getattr__ on the assistant's _ErrorRecoveringStream proxy — stream.get() would have built the response from an empty proxy-local parts manager. Fixed by property-delegating the shadowed attributes to the inner stream, with a regression test.

pip-audit over the new resolution reports a single remaining finding: lupa 2.6 — dev-only (fakeredis lua extra, never in prod images), no fixed release exists.

⚠️ Follow-up required in saas

The saas Dockerfiles mirror this one and consume the synced uv.lock — they need the same one-line git package addition or image builds will fail at uv sync --frozen after the next lock sync. MR: https://gitlab.com/baserow/baserow-saas/-/merge_requests/634

Verification

• Follow the instructions in docs/development/sso-saml.md and verify SAML SSO still works.
• Build the backend image with just build backend latest --no-cache and verify with docker scout cves local:baserow/backend:latest > /tmp/scout.txt the High CVE about pysaml2, cryptography and pyopenssl are gone. The only ones remaining are from the python base image: https://hub.docker.com/layers/library/python/3.14.6-slim-trixie/images/sha256-802bfded3f783b1d84b2022e67e00f8e4b6631d25c5bc3c24736864095a55f97

[Copilot]

Pull request overview

This PR resolves backend Dependabot security alerts by upgrading multiple Python dependencies (notably cryptography/pyopenssl/twisted/pydantic-ai) and introducing a temporary git-sourced fork of pysaml2 to unblock the upgrades. It also updates the enterprise assistant streaming proxy to remain compatible with the newer pydantic-ai internals and adds a regression test for the streaming .get() behavior.

Changes:

• Upgrade backend dependency set in pyproject.toml/uv.lock, including switching pysaml2 to a git SHA-pinned fork via tool.uv.sources.
• Update backend Docker build stages to install git so uv sync --frozen can fetch git-based dependencies.
• Fix _ErrorRecoveringStream attribute shadowing by delegating additional StreamedResponse class/default attributes to the inner stream, with an added regression assertion in enterprise tests.

Reviewed changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
enterprise/backend/tests/baserow_enterprise_tests/assistant/test_retrying_model.py	Extends streaming recovery tests to validate .get() reads parts from the inner stream’s parts manager after pydantic-ai changes.
enterprise/backend/src/baserow_enterprise/assistant/retrying_model.py	Ensures the stream proxy delegates shadowed StreamedResponse attributes (incl. _parts_manager) to the wrapped stream.
changelog/entries/unreleased/bug/upgrades_backend_dependencies_to_fix_known_security_vulnerab.json	Adds an unreleased changelog entry covering the backend security dependency upgrades.
backend/uv.lock	Updates locked dependency resolution (including pysaml2 git source and multiple version bumps) to address CVEs.
backend/pyproject.toml	Bumps key pinned versions and adds tool.uv.sources override to consume the pysaml2 fork by immutable SHA.
backend/Dockerfile	Installs git in relevant build/dev stages so uv can fetch git-sourced dependencies during image builds.

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[github-actions]

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
enterprise/backend/src/baserow_enterprise/assistant
retrying_model.py					488-496
Project Total

This report was generated by python-coverage-comment-action

[alamin-br]

Looks good to me 🚀