# CVE-2026-57497

## Summary

- **CVE ID:** CVE-2026-57497
- **Severity:** MEDIUM
- **CVSS Score:** 5.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)
- **CWE:** CWE-770
- **Published:** Sep 14, 2026
- **Last Modified:** Sep 14, 2026

## Description

webtransport-go is an implementation of the WebTransport protocol. Prior to 0.11.1, Session.parseNextCapsule() in session.go skips an unknown WebTransport capsule on the HTTP/3 request stream by calling io.ReadAll on the capsule reader, retaining the complete declared capsule body in memory. A malicious peer can send a large unknown capsule and cause a client or server to allocate memory for the full payload; QUIC flow control does not bound the total retained allocation because reading advances the flow-control window while the received bytes remain in memory. The resulting memory and resource exhaustion can disrupt or crash the affected process. This issue is fixed in version 0.11.1.

## Affected Products

- quic-go — webtransport-go (< 0.11.1)

## References

- [CNA](https://github.com/quic-go/webtransport-go/security/advisories/GHSA-g35j-m5xg-vh3q)
- [CNA](https://github.com/quic-go/webtransport-go/pull/290)
- [CNA](https://github.com/quic-go/webtransport-go/commit/3aecd11736579530ff067651c30a543eb0b4b8c4)
- [CNA](https://github.com/quic-go/webtransport-go/releases/tag/v0.11.1)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.47%
- **EPSS Percentile:** 39.5

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-17._