fix(agentex-ui): bump nanoid 3.3.16 -> 3.3.18 (CVE-2026-67213) - #398

Summary

Remediates CVE-2026-67213 (HIGH) in nanoid for the agentex-ui service.

nanoid before 3.3.17 / 5.1.6 enters an infinite loop when customAlphabet() or
customRandom() is called with size = 0 — the generation loop never reaches its exit
condition. Availability impact where the size is attacker-influenced.

Why the 3.x line and not 5.1.6

The advisory lists two fixed versions (3.3.17, 5.1.6). 3.3.x is the correct target here:
postcss imports nanoid as CommonJS — require('nanoid/non-secure')
(postcss/lib/input.js:3) — and
nanoid 5.x is ESM-only ("type": "module"). Pinning 5.1.6 would resolve cleanly and then
break postcss at runtime. Staying same-major keeps this a lockfile-only change.

Applied through the existing overrides block, the convention already used in this
manifest for exactly this purpose (cross-spawn, postcss, sharp, tar). The floor is
^3.3.17 (the advisory's fixed version); every version that range can select is
advisory-clean, and it resolved to the latest such release, 3.3.18.

Version gate

• OSV for nanoid@3.3.17 and @3.3.18: zero known advisories.
• Satisfies postcss's declared nanoid: ^3.3.16, so no constraint is violated.
• engines: node ^10 || ^12 || ^13.7 || ^14 || >=15.0.1 — compatible with node 20 (Dockerfile + CI).

Behavior contract (every version crossed)

Read both releases crossed, not just the endpoints:

• 3.3.17 — the security fix. Source diff vs 3.3.16 is exactly one line: if (size <= 0) return ''.
  The prior behavior was an infinite hang, so no caller can depend on it. No change to error types,
  return shapes, defaults, or coercions.
• 3.3.18 — only async/index.native.js (React Native infinite-loop fix) + README. Core
  index.cjs is byte-identical to 3.3.17; inert for a Next.js server/browser target.
• nanoid/non-secure — the only entry point postcss uses — is byte-identical across 3.3.16 -> 3.3.18.
• Target declares no dependencies and no peerDependencies, so the transitive closure is nanoid alone.
• No first-party code in agentex-ui imports nanoid, customAlphabet, or customRandom.

Upstream tracker sweep: ai/nanoid#605 is this exact
CVE, closed as fixed by 3.3.17. No open regression/breaking issues against 3.3.17 or 3.3.18.

Validation

All run locally with npm 10.9.4 / node 20 parity (matching agentex-ui/Dockerfile and the
CI workflow) — not the sandbox default npm 12:

• npm ci — passes, lockfile internally consistent and not rewritten (the exact CI + Docker gate)
• npm ls nanoid --all — single instance: nanoid@3.3.18 overridden
• npm run typecheck (CI job) — clean
• npm run lint (CI job) — no ESLint warnings or errors
• npm run test:run — 75/75 tests pass (11 files)
• npm run build — full production build succeeds, all 10 routes generated (exercises postcss/Tailwind)
• Direct CVE repro: customAlphabet('abcdef',10)(0) and customRandom(...)(0) now return ""
  in ~1ms instead of hanging; normal 10-char generation unaffected
• Consumer smoke: postcss.parse() works, nanoid/non-secure export intact

Diff scope

Two files, +4/-3. Exactly one lockfile package entry changed (node_modules/nanoid);
byte-compared the before/after lock to confirm no other entry differs. lockfileVersion stays
3, resolved stays on the public npm registry, no file-mode changes, no application-code
changes, no dependency additions or removals.

Note: regenerating with CI-parity npm 10 initially stripped the libc metadata field from four
@next/swc-linux-* optional binaries (npm 11+ emits it, npm 10 does not). That drift is unrelated
to this fix and would affect musl/glibc native-binary selection, so it was reverted — the final
diff carries the nanoid change only.

Greptile Summary

The PR raises the transitive nanoid version used by agentex-ui from 3.3.16 to 3.3.18 to remediate CVE-2026-67213.

• Adds a ^3.3.17 nanoid override using the manifest’s existing override mechanism.
• Updates the lockfile resolution and integrity metadata to nanoid 3.3.18.

_{Reviews (1): Last reviewed commit: "fix(agentex-ui): bump nanoid 3.3.16 -> 3..." | Re-trigger Greptile}