CVE-2026-21435

MEDIUM

5.3

Description

webtransport-go is an implementation of the WebTransport protocol. Prior to v0.10.0, an attacker can cause a denial of service in webtransport-go by preventing or indefinitely delaying WebTransport session closure. A malicious peer can withhold QUIC flow control credit on the CONNECT stream, blocking transmission of the WT_CLOSE_SESSION capsule and causing the close operation to hang. This vulnerability is fixed in v0.10.0.

CVE Details

CVSS v3.1 Score5.3

SeverityMEDIUM

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published2/12/2026

Last Modified2/19/2026

Sourcenvd

Honeypot Sightings0

Affected Products

quic-go:webtransport-go

Weaknesses (CWE)

CWE-400

References

https://github.com/quic-go/webtransport-go/releases/tag/v0.10.0(security-advisories@github.com)

https://github.com/quic-go/webtransport-go/security/advisories/GHSA-px4r-g4p3-hhqv(security-advisories@github.com)

IOC Correlations

No correlations recorded

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