CVE-2026-57497

Medium

Description

webtransport-go is an implementation of the WebTransport protocol. Prior to 0.11.1, Session.parseNextCapsule() in session.go skips an unknown WebTransport capsule on the HTTP/3 request stream by calling io.ReadAll on the capsule reader, retaining the complete declared capsule body in memory. A malicious peer can send a large unknown capsule and cause a client or server to allocate memory for the full payload; QUIC flow control does not bound the total retained allocation because reading advances the flow-control window while the received bytes remain in memory. The resulting memory and resource exhaustion can disrupt or crash the affected process. This issue is fixed in version 0.11.1.

SeverityMedium
CVSS5.3
Exploit probability—
ProductGithub.com/quic-go/webtransport-go
PublishedSep 14, 2026
First seenSep 14, 2026

How to fix

Update
  • github.com/quic-go/webtransport-go0.11.1 or later

Affected products

ProductAffected versionsFixed in
github.com/quic-go/webtransport-goGov < 0.11.10.11.1

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CVE-2026-57497 · Github.com/quic-go/webtransport-go · Dark Radar