Bump undici and hardhat

[dependabot]

Bumps undici to 6.27.0 and updates ancestor dependency hardhat. These dependencies need to be updated together.

Updates undici from 5.21.0 to 6.27.0

Release notes

Sourced from undici's releases.

v6.27.0

⚠️ Security Release

This release line addresses 4 security advisories.

Action required: Upgrade to undici 6.27.0 or later.

npm install undici@^6.27.0

Note on patched version: the v6 fixes shipped in v6.27.0, not 6.26.0 — v6.26.0 contains only the chunked-EOF fix (#5308) and the version bump, none of the security fixes below.

The v6 line is not affected by the SOCKS5 advisories (GHSA-vmh5-mc38-953g, GHSA-hm92-r4w5-c3mj), the shared-cache disclosure (GHSA-pr7r-676h-xcf6), or the 8.x-only WebSocket regression (GHSA-38rv-x7px-6hhq).

Summary

Advisory	CVE	Severity (CVSS)	Fixed in	Fix commit
GHSA-vxpw-j846-p89q	CVE-2026-12151	High (7.5)	6.27.0	b7f252e7
GHSA-p88m-4jfj-68fv	CVE-2026-9679	Moderate (5.9)	6.27.0	25efa447
GHSA-g8m3-5g58-fq7m	CVE-2026-11525	Low (3.7)	6.27.0	25efa447
GHSA-35p6-xmwp-9g52	CVE-2026-6733	Low (3.7)	6.27.0	f4c31d60

---

High severity

WebSocket DoS via fragment count bypass — CVE-2026-12151

GHSA-vxpw-j846-p89q · CWE-400, CWE-770 Fix: b7f252e7 Backport WebSocket maxPayloadSize fixes (#5423, backported to v6 in #5428)

A malicious WebSocket server can stream a large number of small or empty continuation frames. Undici enforced a limit on cumulative payload size but did not limit the number of fragments per message, leading to unbounded memory growth and denial of service. All releases from 6.17.0 onward are affected.

• Affected: applications using new WebSocket(...) or WebSocketStream against untrusted endpoints.
• Workaround: none — upgrade is required.

---

Moderate severity

HTTP header injection via Set-Cookie percent-decoding — CVE-2026-9679

... (truncated)

Commits

• 551138c Bumped v6.27.0 (#5431)
• b7f252e Backport WebSocket maxPayloadSize fixes to v7.x (#5423) (#5428)
• 25efa44 fix(cookies): preserve values and parse SameSite strictly
• f4c31d6 fix: guard idle socket validation to skip fresh sockets (#5400)
• 768beac Bumped v6.26.0 (#5323)
• 7917b25 fix: validate EOF for chunked h1 responses (#5308)
• 3420499 Bumped v6.25.0 (#5029)
• d7a1e55 feat: add configurable maxPayloadSize for WebSocket (#4955)
• a9d1848 Do not mark v6.x releases as latest
• 0126586 Ignore local agent configuration files
• Additional commits viewable in compare view

Maintainer changes

This version was pushed to npm by GitHub Actions, a new releaser for undici since your current version.

Install script changes

This version modifies prepare script that runs during installation. Review the package contents before updating.

Updates hardhat from 2.13.0 to 3.9.0

Release notes

Sourced from hardhat's releases.

Hardhat v3.9.0

This release adds support for excluding files from test coverage instrumentation and reporting (i.e. npx hardhat test --coverage).

Changes

• #8380 0fd498d Thanks @​kanej! - Added support for coverage.skipFiles, a list of globs of Solidity files to exclude from coverage instrumentation and reporting during a --coverage run.

• #8383 1660f1e Thanks @​schaable! - Fixed an intermittent "Provider for provided chain type does not exist" error that could occur when multiple network connections were created concurrently.

• #8371 287620e Thanks @​gultekinmakif! - Account overrides that share an address with the network's built-in genesis accounts are now correctly merged into a single genesis entry.

• #8375 931a5f0 Thanks @​schaable! - Suppressed the solc initcode size warning for Solidity test contracts and when running under --coverage.

• #8372 5f6aff2 Thanks @​gultekinmakif! - Improved validation for initialDate network configuration. Invalid Date objects and unparseable date strings are now rejected during config loading rather than causing a runtime error later.

---

💡 The Nomic Foundation is hiring! Check our open positions.

---

Hardhat v3.8.0

This release includes two improvements: a warning is now printed if a plugin is imported in hardhat.config.ts but not included in the plugins array and node:test now more cleanly displays Solidity errors.

Changes

• #8339 f21390f Thanks @​alcuadrado! - Added definePlugin, a new helper exported from hardhat/plugins. Plugin authors should wrap their plugin literal with it so the default export of their index module becomes:

  import type { HardhatPlugin } from "hardhat/types/plugins";
  import { definePlugin } from "hardhat/plugins";
  const hardhatPlugin: HardhatPlugin = definePlugin({
  id: "my-plugin",
  // ...
  });
  export default hardhatPlugin;

  definePlugin returns its argument unchanged and, as a side effect, registers the plugin's id in a process-wide registry of loaded plugins. Hardhat's CLI uses that registry to warn when a plugin is imported but missing from the user's plugins array.

• #8339 19c6927 Thanks @​alcuadrado! - Hardhat now warns when a plugin is imported in your Hardhat config file but missing from the plugins array. The warning is printed to stderr after the runtime environment is created, listing the offending plugins and pointing the user at the fix.

  If your Hardhat config file is written in TypeScript, for the warning to be reliable your project's tsconfig.json must enable verbatimModuleSyntax: true. Without it, TypeScript deletes unused default-value imports, so an unused plugin can't be detected.

• #8336 86bfe66 Thanks @​Wodann! - - Fixed default gas limit of Solidity test runner when a custom transaction gas cap (EIP-7825) or block gas limit is specified

  • Fixed process deadlock/hang when dropping a provider with interval mining and logging enabled
  • Print more detailed error descriptions for EVM, invariant fuzz, and cheatcode errors

• #8345 9d5b96c Thanks @​alcuadrado! - Add .solidityStack property to the SolidityError exceptions generated by EDR

... (truncated)

Changelog

Sourced from hardhat's changelog.

3.9.0

Minor Changes

• #8380 0fd498d Thanks @​kanej! - Added support for coverage.skipFiles, a list of globs of Solidity files to exclude from coverage instrumentation and reporting during a --coverage run.

Patch Changes

• #8383 1660f1e Thanks @​schaable! - Fixed an intermittent "Provider for provided chain type does not exist" error that could occur when multiple network connections were created concurrently.

• #8371 287620e Thanks @​gultekinmakif! - Account overrides that share an address with the network's built-in genesis accounts are now correctly merged into a single genesis entry.

• #8375 931a5f0 Thanks @​schaable! - Suppressed the solc initcode size warning for Solidity test contracts and when running under --coverage.

• #8372 5f6aff2 Thanks @​gultekinmakif! - Improved validation for initialDate network configuration. Invalid Date objects and unparseable date strings are now rejected during config loading rather than causing a runtime error later.

3.8.0

Minor Changes

• #8339 f21390f Thanks @​alcuadrado! - Added definePlugin, a new helper exported from hardhat/plugins. Plugin authors should wrap their plugin literal with it so the default export of their index module becomes:

  import type { HardhatPlugin } from "hardhat/types/plugins";
  import { definePlugin } from "hardhat/plugins";
  const hardhatPlugin: HardhatPlugin = definePlugin({
  id: "my-plugin",
  // ...
  });
  export default hardhatPlugin;

  definePlugin returns its argument unchanged and, as a side effect, registers the plugin's id in a process-wide registry of loaded plugins. Hardhat's CLI uses that registry to warn when a plugin is imported but missing from the user's plugins array.

• #8339 19c6927 Thanks @​alcuadrado! - Hardhat now warns when a plugin is imported in your Hardhat config file but missing from the plugins array. The warning is printed to stderr after the runtime environment is created, listing the offending plugins and pointing the user at the fix.

  If your Hardhat config file is written in TypeScript, for the warning to be reliable your project's tsconfig.json must enable verbatimModuleSyntax: true. Without it, TypeScript deletes unused default-value imports, so an unused plugin can't be detected.

Patch Changes

• #8336 86bfe66 Thanks @​Wodann! - - Fixed default gas limit of Solidity test runner when a custom transaction gas cap (EIP-7825) or block gas limit is specified

  • Fixed process deadlock/hang when dropping a provider with interval mining and logging enabled
  • Print more detailed error descriptions for EVM, invariant fuzz, and cheatcode errors

• #8345 9d5b96c Thanks @​alcuadrado! - Add .solidityStack property to the SolidityError exceptions generated by EDR

... (truncated)

Commits

• 59c0787 Version Packages
• 904a944 Merge pull request #8380 from NomicFoundation/feat/coverage-skip-files
• 9602831 feat: skip instrumentation for coverage.skipFiles matches
• ac16d41 Merge pull request #8371 from gultekinmakif/fix/genesis-state-merge
• 84a0b5d test(network-manager): cover empty-list and new-entry paths for mergeGenesisS...
• b96bf45 test(network-manager): cover mergeGenesisState with crafted address collisions
• b089f07 fix(network-manager): favor user override over chain default in mergeGenesisS...
• aea8440 refactor(network-manager): extract genesis-state merge loop to mergeGenesisState
• f69ec6a fix(network-manager): call genesisState.set when merging an existing override
• 75de11d test(network-manager): refactor test desc
• Additional commits viewable in compare view

Maintainer changes

This version was pushed to npm by GitHub Actions, a new releaser for hardhat since your current version.

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting @dependabot rebase.

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