CVE-2026-21435webtransport-go is an implementation of the WebTransport protocol.
Updated under an hour ago ()
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It affects quic-go webtransport-go. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.5 HIGH (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-400
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Analyzed
- Record last updated
- Jun 17, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
quic-go webtransport-go quic-go:webtransport-go | before 0.10.0 | NVD |
References
- https://github.com/quic-go/webtransport-go/releases/tag/v0.10.0product, release-notes
- https://github.com/quic-go/webtransport-go/security/advisories/GHSA-px4r-g4p3-hhqvvendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.