Improper Resource Shutdown or Release Affecting github.com/quic-go/webtransport-go package, versions <0.10.0
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-GOLANG-GITHUBCOMQUICGOWEBTRANSPORTGO-15279233
- published13 Feb 2026
- disclosed12 Feb 2026
- creditUnknown
Introduced: 12 Feb 2026
CVE-2026-21435 (opens in a new tab)How to fix?
Upgrade github.com/quic-go/webtransport-go to version 0.10.0 or higher.
Overview
Affected versions of this package are vulnerable to Improper Resource Shutdown or Release via the CloseWithError function. An attacker can cause the process to hang indefinitely by withholding QUIC flow control credit on the CONNECT stream, which prevents the transmission of the WT_CLOSE_SESSION capsule and blocks session closure.