fix: update webtransport-go to v0.11.1 - #3532
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webtransport-go v0.11.1 fixes CVE-2026-57497 / GHSA-g35j-m5xg-vh3q, unbounded buffering of unknown WebTransport capsules. A peer could send a large capsule of an unrecognized type and make the receiver hold the whole body in memory. v0.11.1 drains it to io.Discard. v0.11.1 requires quic-go v0.60.0, so quic-go moves with it. v0.11.x speaks WebTransport draft-15: the client sends the webtransport-h3 :protocol token and SETTINGS_WT_ENABLED, and no longer accepts a server that advertises only the draft-06 codepoint. Dialing a peer on webtransport-go v0.10.0 or older will fail. Inbound sessions from those peers still work, since the server accepts both generations, and browsers are unaffected.
webtransport-go v0.11.1 speaks a newer WebTransport draft, so go-libp2p-head cannot dial peers still on the older one. Browser to go-libp2p is unaffected, which is the direction WebTransport exists for, and go to go falls back to /quic-v1. Also drops the go-v0.45 entry, which no longer exists in the interop matrix.
lidel
marked this pull request as ready for review
July 27, 2026 17:31
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sukunrt
approved these changes
Jul 27, 2026
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Problem
go-libp2p ships webtransport-go v0.10.0, which has two problems.
Memory exhaustion. Already-public GHSA-g35j-m5xg-vh3q (CVE-2026-57497): unknown WebTransport capsules are read with
io.ReadAll, so a peer can make the receiver buffer an arbitrarily large capsule body.Browser interop is aging out. WebTransport is here so browsers can reach a go-libp2p node. Browsers only dial, never listen, so browser to go-libp2p is the direction worth optimising for. v0.10.0 speaks only the oldest version of the handshake, and omits a setting Safari 26.4+ wants (quic-go/webtransport-go#262).
Fix
webtransport-go v0.11.1 plus quic-go v0.60.0, which v0.11.1 requires. No source changes, since v0.11.1 still exports
Dialer.Browsers keep working, current and future ones
WebTransport over HTTP/3 is still an IETF draft, draft-ietf-webtrans-http3, and libp2p builds on it (libp2p WebTransport spec). A session identifies itself with two values on the wire: an Extended CONNECT
:protocoltoken, and an HTTP/3 SETTINGS codepoint. Version 15 of the draft (March 2026) renamed both:webtransportbecomeswebtransport-h30x2b603742becomes0x2c7cf000v0.11.1's server sends and accepts both spellings, so it answers either generation of client:
webtransport-h3nor0x2c7cf000appears anywhere in quiche.SETTINGS_WT_MAX_SESSIONSvalue Safari 26.4+ expects and v0.10.0 never sent.So this is the change that keeps browsers able to reach go-libp2p, rather than one that risks it.
The go-to-go regression, which does not matter
A node on v0.11.x can no longer dial a peer still on v0.10.0 over WebTransport. The reverse still works: old peers can dial this node fine.
We do not care. Go to go connections use
/quic-v1, which every node announces on the same UDP port, and the dial ranker prefers it over WebTransport anyway. WebTransport is there for browsers, and browsers are unaffected. It also resolves itself as the network upgrades.Verified with a real browser: Firefox 153 via
@libp2p/webtransportcompletes a full dial against a v0.11.1 listener.