[dependabot]

Bumps undici from 6.28.0 to 6.29.1.

Release notes

Sourced from undici's releases.

v6.29.1

Security fixes

High severity

Denial of service via TLS 1.2 certificate-changing renegotiation

CVE-2026-87018 · GHSA-qrxm-fqhp-jwvm

A malicious or compromised HTTPS server could crash the Node.js process by initiating TLS 1.2 renegotiation and presenting a different, CA-trusted certificate whose hostname did not match the requested host. The resulting socket error reached an assertion in undici's HTTP/1.1 and HTTP/2 connection handling. This release handles post-connect certificate errors without terminating the process.

TLS certificate validation bypass through dropped Agent options

CVE-2026-109383 · GHSA-2m5v-pch6-74hx

Agent used a JSON-based clone for constructor options, which silently removed function-valued TLS options such as checkServerIdentity. Applications relying on custom certificate or public-key verification could therefore accept a certificate that the callback was intended to reject. This release preserves TLS options when creating per-origin dispatchers.

Denial of service through excessive Content-Encoding values

CVE-2026-109869 · GHSA-xjj6-f33q-929c

A malicious HTTP server could crash the Node.js process by returning more than five content codings and closing the connection before sending the body. Although fetch() rejected the response, an error from an orphaned internal stream could remain unhandled. This release validates the content-encoding chain before creating the body stream and aborts oversized chains safely.

Medium severity

Denial of service through unbounded EventSource parser state

CVE-2026-109924 · GHSA-4qv8-2p9j-2685

A malicious Server-Sent Events endpoint could exhaust process memory by sending many tiny data: fields without completing an event, or by splitting an unfinished line across many chunks. This release bounds retained EventSource parser state, including field counts, buffered chunks, unfinished-line length, and retained field data.

Denial of service through unbounded automatic WebSocket PONG buffering

CVE-2026-109932 · GHSA-9fm3-97px-rjf6

A malicious WebSocket server could exhaust process memory by flooding the client with PING frames while not reading the automatic PONG responses. undici previously ignored socket backpressure and allowed the outbound queue to grow without bound. This release pauses frame parsing when PONG writes encounter backpressure and resumes after the socket drains.

What's Changed

• [v6.x] fix(fetch): fix aborting Streams (#3754) by @​mrityunjay-pandey in nodejs/undici#6000

Full Changelog: nodejs/undici@v6.29.0...v6.29.1

v6.29.0

What's Changed

• [v6.x] fix(retry): settle exposed body on terminal failure by @​mcollina in nodejs/undici#5778
• Backport upgrade diagnostics lifecycle fixes to v6.x by @​BridgeAR in nodejs/undici#5833
• test: synchronize the issue-3356 body timeout by @​BridgeAR in nodejs/undici#5834

... (truncated)

Commits

• 8c57f6c [Release] v6.29.1 (#6023)
• 39f93e1 fix(websocket): bound automatic PONG writes under backpressure
• c43b23f fix(eventsource): bound retained SSE parser state
• 1325a87 fix(fetch): abort excessive content encoding responses
• 8c59f6b fix: preserve Agent connection options
• b40fbfc fix: handle post-connect TLS certificate errors
• 407630a [v6.x] fix(fetch): fix aborting Streams (#3754) (#6000)
• e1d0501 Bumped v6.29.0 (#5888)
• 57ac4de test: synchronize the issue-3356 body timeout (#5834)
• 6d44174 Backport upgrade diagnostics lifecycle fixes to v6.x (#5833)
• Additional commits viewable in compare view

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[codspeed]

Merging this PR will not alter performance

✅ 15 untouched benchmarks

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_{Comparing dependabot/npm_and_yarn/undici-6.29.1 (42c4bd4) with main (c386862)}