CVE-2026-21435

MEDIUM

webtransport-go < 0.10.0 - Denial of Service via WebTransport Session Closure Blocking

Title source: llm

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.

References (2)

Core 2

Core References

Vendor Advisory x_refsource_confirm

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

Release Notes x_refsource_misc

https://github.com/quic-go/webtransport-go/releases/tag/v0.10.0

Scores

CVSS v3 5.3

EPSS 0.0041

EPSS Percentile 32.8%

Attack Vector NETWORK

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

CISA SSVC

Vulnrichment

Exploitation none

Automatable yes

Technical Impact partial

Details

CWE

CWE-400

Status published

Products (2)

quic-go/webtransport-go < 0.10.0

quic-go/webtransport-go 0 - 0.10.0Go

Published Feb 12, 2026

Tracked Since Feb 18, 2026