CVE-2026-21434
Description
webtransport-go is an implementation of the WebTransport protocol. From 0.3.0 to 0.9.0, an attacker can cause excessive memory consumption in webtransport-go's session implementation by sending a WT_CLOSE_SESSION capsule containing an excessively large Application Error Message. The implementation does not enforce the draft-mandated limit of 1024 bytes on this field, allowing a peer to send an arbitrarily large message payload that is fully read and stored in memory. This allows an attacker to consume an arbitrary amount of memory. The attacker must transmit the full payload to achieve the memory consumption, but the lack of any upper bound makes large-scale attacks feasible given sufficient bandwidth. This vulnerability is fixed in 0.10.0.
CVSS Details
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Threat Intelligence
Weaknesses 1
Affected Products 1
| Vendor | Product | Version | Range |
|---|---|---|---|
| quic-go | webtransport-go | * | ≥0.3.0 – <0.10.0 |
References 2
- github.com https://github.com/quic-go/webtransport-go/releases/tag/v0.10.0
- github.com https://github.com/quic-go/webtransport-go/security/advisories/GHSA-g6x7-jq8p-6q9q
Remediation
No remediation data recorded yet
Check vendor advisories and the NVD entry for patch availability.