CVE-2026-57497: webtransport-go Memory Exhaustion Attack Due To Vulnerability

MODERATE
Advisory Identifier: GHSA-g35j-m5xg-vh3q
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CVSS 5.3
CWE-770
Published
Advisory Summary

CVE-2026-57497 is a MODERATE (CVSS 5.3) memory exhaustion attack due to vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting webtransport-go libraries in the Go ecosystem. The issue involves memory exhaustion attack due to buffering of unknown capsules. Remediation is available by upgrading affected packages to version 0.11.1.

CVE-2026-57497 at a Glance

CVE Identifier CVE-2026-57497
GHSA Identifier GHSA-g35j-m5xg-vh3q
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-770: Allocation of Resources Without Limits or Throttling
Affected Product webtransport-go
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 5.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability Low (A:L)

How to Fix CVE-2026-57497

To remediate this vulnerability, upgrade all affected webtransport-go dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

github.com/quic-go/webtransport-go fixed: 0.11.1 
Upgrade github.com/quic-go/webtransport-go to 0.11.1
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for github.com/quic-go/webtransport-go

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-57497, inspect your project dependencies for webtransport-go:

inspect dependencies for github.com/quic-go/webtransport-go

Analyze the terminal output to locate any version of webtransport-go in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.11.1), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-770: Allocation of Resources Without Limits or Throttling, where the product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. In webtransport-go, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## Summary An attacker can cause excessive memory allocation in webtransport-go by sending an unknown WebTransport capsule with a large payload. The implementation skips unknown capsules by reading the entire capsule body into memory, instead of draining it without retaining the data. This can lead to memory exhaustion. ## Impact A misbehaving or malicious peer can cause a denial-of-service (DoS) attack against webtransport-go clients or servers by triggering excessive memory allocation, potentially leading to crashes or resource exhaustion. ## Details WebTransport sessions use capsules on the HTTP/3 request stream. Unknown capsule types are ignored, but the capsule body still needs to be consumed before the next capsule can be parsed. webtransport-go used `io.ReadAll` when skipping unknown capsules. Since the capsule reader is only limited by the capsule's declared length, a peer could send a large unknown capsule and cause the receiver to allocate memory for the full capsule body. QUIC flow control limits buffered data, but it does not bound total allocation here, since reading the stream advances the flow control window while retaining the received bytes in memory. ## The Fix webtransport-go now drains unknown capsules to `io.Discard` instead of buffering them. This consumes the capsule body so parsing can continue, without retaining the payload in memory.

CVE-2026-57497 Affected webtransport-go Versions

1 component(s)
Fixed Versions:
0.11.1
Product / Package Ecosystem Affected Versions Fixed Version
github.com/quic-go/webtransport-go
golang/github.com/quic-go/webtransport-go
Go
< 0.11.1
0.11.1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/quic-go/webtransport-go/security/advisories/GHSA-g35j-m5xg-vh3q
webtransport-go Source Repository REPOSITORY
https://github.com/quic-go/webtransport-go/pull/290
Security Fix Commit FIX COMMIT
https://github.com/quic-go/webtransport-go/commit/3aecd11736579530ff067651c30a543eb0b4b8c4
webtransport-go Source Repository REPOSITORY
https://github.com/quic-go/webtransport-go
webtransport-go Release RELEASE
https://github.com/quic-go/webtransport-go/releases/tag/v0.11.1

Frequently Asked Questions

What is CVE-2026-57497?
CVE-2026-57497 is a security vulnerability in webtransport-go involving Memory Exhaustion Attack due to Buffering of Unknown Capsules under CWE-770: Allocation of Resources Without Limits or Throttling.
Which webtransport-go versions are affected?
Affected versions include releases prior to 0.11.1 across affected packages: github.com/quic-go/webtransport-go.
What version fixes CVE-2026-57497?
Upgrading to 0.11.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/quic-go/webtransport-go affected?
Yes, github.com/quic-go/webtransport-go is affected in releases prior to 0.11.1. Upgrade your dependency to 0.11.1 or later.
What is the CVSS score of CVE-2026-57497?
CVE-2026-57497 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
What CWE is associated with CVE-2026-57497?
CVE-2026-57497 is classified under CWE-770: Allocation of Resources Without Limits or Throttling (The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.).
How can I check Go dependencies for CVE-2026-57497?
Run the dependency tree command: 'inspect dependencies for github.com/quic-go/webtransport-go'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-g35j-m5xg-vh3q",
  "modified" : "2026-07-24T20:49:28Z",
  "published" : "2026-07-24T20:49:28Z",
  "aliases" : [ "CVE-2026-57497" ],
  "summary" : "webtransport-go: Memory Exhaustion Attack due to Buffering of Unknown Capsules",
  "details" : "## Summary\n\nAn attacker can cause excessive memory allocation in webtransport-go by sending an unknown WebTransport capsule with a large payload. The implementation skips unknown capsules by reading the entire capsule body into memory, instead of draining it without retaining the data. This can lead to memory exhaustion.\n\n## Impact\n\nA misbehaving or malicious peer can cause a denial-of-service (DoS) attack against webtransport-go clients or servers by triggering excessive memory allocation, potentially leading to crashes or resource exhaustion.\n\n## Details\n\nWebTransport sessions use capsules on the HTTP/3 request stream. Unknown capsule types are ignored, but the capsule body still needs to be consumed before the next capsule can be parsed.\n\nwebtransport-go used `io.ReadAll` when skipping unknown capsules. Since the capsule reader is only limited by the capsule's declared length, a peer could send a large unknown capsule and cause the receiver to allocate memory for the full capsule body.\n\nQUIC flow control limits buffered data, but it does not bound total allocation here, since reading the stream advances the flow control window while retaining the received bytes in memory.\n\n## The Fix\n\nwebtransport-go now drains unknown capsules to `io.Discard` instead of buffering them. This consumes the capsule body so parsing can continue, without retaining the payload in memory.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/quic-go/webtransport-go"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.11.1"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.11.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/quic-go/webtransport-go/security/advisories/GHSA-g35j-m5xg-vh3q"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/quic-go/webtransport-go/pull/290"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/quic-go/webtransport-go/commit/3aecd11736579530ff067651c30a543eb0b4b8c4"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/quic-go/webtransport-go"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/quic-go/webtransport-go/releases/tag/v0.11.1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-24T20:49:28Z",
    "nvd_published_at" : null
  }
}