CLAUDE.md

Guidance for Claude when working in this repository (hacdias/webdav).

Handling security advisories

Advisory state lives on GitHub and is driven with the gh CLI: triage → draft → published, plus closed. Reports are routed as per SECURITY.md; only 5.x is supported.

1. Fetch

# List by state (also: published, draft, closed)
gh api '/repos/hacdias/webdav/security-advisories?state=triage&per_page=100' \
  --jq '.[] | {ghsa_id, severity, summary, state}'

# Full report for one advisory
gh api /repos/hacdias/webdav/security-advisories/GHSA-xxxx-xxxx-xxxx \
  --jq '.summary, "---", .description'

Always pull the published and remaining triage sets too, to dedup against.

2. Verify — do NOT trust the report text

Read the source at HEAD and reproduce the claim; a failing makeTestServer case is better evidence than reading the matcher. Reach one verdict per advisory:

• CONFIRMED — defect exists at HEAD. Quote the exact file:line.
• FIXED — already patched; find the fix commit and the release carrying it.
• FALSE / NOT APPLICABLE — claim is wrong, or targets a different project.
• NOT EXPLOITABLE — pattern exists but no code path reaches the precondition.
• DUPLICATE — of a published advisory, or of another triage advisory.

Common traps:

• "Incomplete fix of a prior advisory." Read the original fix commit and confirm the specific sibling path is still unguarded. GHSA-chxv-mvjv-f92j already cleans paths in newRequest and matches trailing-slash rules against the bare collection.
• Wrong project. Confirm the cited files, symbols, and options exist here — reports sometimes describe a fork or another WebDAV server.
• Containment vs authorization. golang.org/x/net/webdav applies slashClean and keeps requests inside the served root, so "traversal out of directory" is usually not the defect. The real class is the authorization layer disagreeing with the filesystem layer about which file a request names.
• No users: means no authentication, by design — it warns at startup. Not a vulnerability, but it changes the privilege precondition.
• Overlapping reports. Several triage advisories may share one root cause: consolidate into one, close the rest as duplicates.

Record per advisory: verdict, file:line evidence, preconditions (default config? needs directories:? platform-specific? auth required?), disposition.

3. Severity

Set a CVSS v3.1 vector — GitHub derives the score and severity from it, overriding the plain severity field. Encode the real preconditions so the band is defensible: a required configuration or platform (case-insensitive filesystem, directories:) is AC:H; needing an account is PR:L. Rate the base case as a config with a users: block, and note the unauthenticated vector in the body when it is materially worse. Don't let an incomplete-fix follow-up outrank its parent.

gh api -X PATCH /repos/hacdias/webdav/security-advisories/GHSA-xxxx-xxxx-xxxx \
  -f cvss_vector_string='CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N' \
  --jq '{ghsa_id, severity, score: .cvss.score, vector: .cvss.vector_string}'

4. Rewrite the title and body

The title is summary: concise and sentence-case, stating the vulnerability class then the mechanism, e.g. Authorization bypass: path rules can be evaded with dot segments or a bare collection name.

Rewrite description into the sections below, reusing the reporter's own wording where it is accurate. Drop the greeting and anything step 2 disproved. Use ### headings, keep this order, omit what doesn't apply. Keep the maintainer's voice — first person belongs only in quoted PoC steps.

Send it as a file so the Markdown survives shell quoting:

jq -Rs '{description: .}' desc.md \
  | gh api -X PATCH .../security-advisories/GHSA-xxxx-xxxx-xxxx --input -

5. Affected versions

The package is always {ecosystem: "go", name: "github.com/hacdias/webdav/v5"}. vulnerable_version_range ends at the last release before the fix; add a lower bound when the defect was introduced in a known version, confirming with git log -S and git tag --contains. patched_versions is the release carrying the fix.

printf '%s' '{"vulnerabilities":[{"package":{"ecosystem":"go","name":"github.com/hacdias/webdav/v5"},"vulnerable_version_range":">= 5.10.0, <= 5.14.1","patched_versions":"5.14.2","vulnerable_functions":[]}]}' \
  | gh api -X PATCH .../security-advisories/GHSA-xxxx-xxxx-xxxx --input -

6. Move state

gh api -X PATCH .../security-advisories/GHSA-xxxx-xxxx-xxxx -f state=draft    # ready to publish
gh api -X PATCH .../security-advisories/GHSA-xxxx-xxxx-xxxx -f state=closed   # duplicate / N-A / not-exploitable

• CONFIRMED → fix, release, set patched_versions → draft, then publish once the release is out.
• DUPLICATE / NOT APPLICABLE / NOT EXPLOITABLE → closed.

The REST API cannot post advisory comments. Replies to reporters must be posted manually in the UI — draft the text for the maintainer.