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.
Published: 2026-09-14
Score: 5.3 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-g35j-m5xg-vh3q webtransport-go: Memory Exhaustion Attack due to Buffering of Unknown Capsules
History

Mon, 14 Sep 2026 21:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Mon, 14 Sep 2026 21:00:00 +0000

Type Values Removed Values Added
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.
Title webtransport-go: Memory Exhaustion Attack due to Buffering of Unknown Capsules
Weaknesses CWE-770
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}

Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-14T20:06:48.086Z

Reserved: 2026-06-24T14:53:40.111Z

Link: CVE-2026-57497

cve-icon Vulnrichment

Updated: 2026-09-14T19:22:15.425Z

cve-icon NVD

Status : Received

Published: 2026-09-14T17:17:49.097

Modified: 2026-09-14T20:16:48.567

Link: CVE-2026-57497

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-770

    Allocation of Resources Without Limits or Throttling