CVE-2026-85024

Impact

undici's WebSocket client (including Node.js's bundled globalThis.WebSocket) crashes the entire Node.js process when a remote WebSocket peer sends a permessage-deflate compressed message that crosses the decompressed-payload size limit and then contains a malformed DEFLATE block. In lib/web/websocket/permessage-deflate.js, the size-limit cleanup calls removeAllListeners() on the internal zlib InflateRaw, removing its error listener, but leaves the stream running. The inflater then emits a Z_DATA_ERROR with no listener attached, which Node.js treats as a fatal unhandled error event and terminates the process. Application error/close handlers on the public WebSocket cannot observe or prevent this, because the failing object is the internal InflateRaw.

A malicious or compromised WebSocket server can crash a client with a single connection, unauthenticated and without any application mistake. The attack is asymmetric (about 130 KB on the wire expands past the limit) and can be repeated on reconnect (crash loop).

Affected applications are those using the undici WebSocket client (new WebSocket(...)) or Node.js's bundled globalThis.WebSocket that can be induced to connect to an attacker-controlled or compromised WebSocket endpoint.

Patches

Upgrade to undici v6.28.1, v7.29.1 or v8.10.2.

Workarounds

No workaround is available.

undici bundles a WebSocket client whose permessage-deflate size-limit cleanup removes all listeners from the internal zlib inflate stream, including its error listener, while that stream can still emit. When a remote peer sends a compressed payload that crosses the built-in 128 MiB decompressed-payload limit and then contains a malformed DEFLATE byte, the inflate stream emits a data error with no listener attached, which Node.js treats as a fatal unhandled error and terminates the entire process. Exploitation is remote and unauthenticated, requires no application mistake, and is asymmetric, since roughly 130 KB on the wire expands past the limit and crashes the process, and reconnecting can repeat the crash. This affects undici versions from 6.25.0 up to 6.28.1, from 7.28.0 up to 7.29.1, and from 8.1.0 up to 8.10.2. Users should upgrade to undici 6.28.1, 7.29.1, or 8.10.2.

TuxCare rebuilt undici to address 1 CVE. Fixed in 7.29.0-tuxcare.1.

TuxCare rebuilt undici to address 1 CVE. Fixed in 7.28.0-tuxcare.2.

TuxCare rebuilt undici to address 2 CVEs. Fixed in 6.28.0-tuxcare.2.

TuxCare rebuilt undici-types to address 1 CVE. Fixed in 7.29.0-tuxcare.1.

This update for pi-coding-agent fixes the following issues:

Changes in pi-coding-agent:

• Update to version 1.0.4 (1.0.3 was superseded the same day and never submitted):

  • BREAKING: provider azure-openai-responses renamed to azure, now also serving Azure Foundry Chat Completions (azure/deepseek-v4-pro first). Rename the provider key in auth.json (or run /login again), models.json and settings.json (defaultProvider, enabledModels and modelThinkingLevels); sessions on the old provider fall back and lose prompt cache. AZURE_OPENAI_* env vars unchanged
  • --tools and --exclude-tools take *-patterns and --no-mcp disables MCP for one run; --tools keeps MCP tools unless an entry starts with mcp__
  • Codemode read() on image files yields an image block image() shows, and image() also saves each image to a temp file for later turns
  • Fix fenced-code highlighting past the first line, MCP OAuth native-client registration, MCP shutdown racing a connecting server, Bedrock stalled-stream retries and frozen codemode built-ins, plus ChatGPT-login, EIO-on-closed-terminal and output-file-permission fixes
  • Many more fixes and improvements; see upstream's release notes for the full list

• Refresh the vendored node_modules 1.0.2 -> 1.0.4: the ten @earendil-works packages move to 1.0.4; nanoid, postcss and vite move too but are dev-only and not shipped. Still 119 shipped modules and the licence union is unchanged

  • CVE-2026-102276 (boo#1283188): brace-expansion is 5.0.12, above the 5.0.10 fix floor, so the package is not affected by it
  • CVE-2026-102277 (boo#1283392) and CVE-2026-102278 (boo#1283412): brace-expansion is 5.0.12, at the 5.0.12 and above the 5.0.11 fix floors, so the package is not affected by them

• Update to version 1.0.2: patch releases on the 1.0 API, with no breaking changes

  • models.json takes samplingParamsByThinkingLevel next to the existing samplingParams, so an OpenAI-compatible model can set temperature, top_p and the like separately for off, minimal, low, medium, high, xhigh and max. Model defaults, the effective level's override and the request are merged per key, modelOverrides merges per level, and the levels are pi's own, not the provider's thinkingLevelMap values. Only openai-completions, openai-responses and azure-openai-responses apply them
  • MCP servers can be enabled, disabled or re-scoped per project from a .pi/mcp.json entry without a command or url, and /mcp toggles a user-level server for the current project
  • oauth.clientRegistration: "cimd" identifies pi by its Client ID Metadata Document instead of dynamic client registration
  • pi.registerToolRenderer() picks how calls to a tool that is not registered yet are drawn, such as MCP tools in a resumed session
  • Cloudflare's Clef and Clef Flash classifier models are usable from codemode scripts and extensions
  • A codemode script printing in a loop now fails at 16 Mi characters or 100000 items instead of running pi out of memory
  • MCP tool calls in resumed sessions and HTML exports no longer render fully expanded until their server connects
  • JPEG, GIF and WebP images that extensions draw through Image now appear in Kitty, Ghostty, WezTerm and Warp, and fullscreen Kitty images no longer collapse to a one-row strip after scrolling in WezTerm
  • Many more fixes and improvements; see upstream's release notes for the full list

• Refresh the vendored node_modules over 1.0.0 -> 1.0.2: the ten @earendil-works packages move to 1.0.2, with pi-telemetry the one that was already at 1.0.2 in the 1.0.1 tree, plus @anthropic-ai/sdk to 0.129.0. No module leaves or joins the 119 shipped ones and the licence union is unchanged

  • CVE-2026-102276 (boo#1283188): brace-expansion is 5.0.12, above the 5.0.10 fix floor, so the package is not affected by it. Upstream's 1.0.1 made…

Root has patched CVE-2026-85024 in the undici package for Root:npm. Multiple fixed versions available.