cvedb.io
CVE-2026-21434
MEDIUM · CVSS 5.3
EPSS exploitation probability: 0%
Published 2026-02-12T19:15:51.333 · Last modified 2026-06-17T10:18:39.907

Summary

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.

Affected products

quic-go — webtransport-go

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.