GHSA-2F2X-8MWP-P2GC
Vulnerability from github – Published: 2026-02-12 15:29 – Updated: 2026-02-12 22:07Summary
An attacker can cause unbounded memory consumption repeatedly creating and closing many WebTransport streams. Closed streams were not removed from an internal session map, preventing garbage collection of their resources.
Details
webtransport-go maintains an internal map tracking WebTransport streams (both unidirectional and bidirectional) belonging to a session. In affected versions, entries for closed streams were not removed from this map, causing the map to grow indefinitely as streams were created and closed.
A malicious peer can exploit this by opening large numbers of streams and closing them, leading to steady memory growth proportional to the number of closed streams.
The Fix
webtransport-go now removes closed streams from the internal map upon closure. This allows the associated resources to be garbage collected, bounding memory usage to active streams only.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 0.9.0"
},
"package": {
"ecosystem": "Go",
"name": "github.com/quic-go/webtransport-go"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.10.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-21438"
],
"database_specific": {
"cwe_ids": [
"CWE-401",
"CWE-459"
],
"github_reviewed": true,
"github_reviewed_at": "2026-02-12T15:29:11Z",
"nvd_published_at": "2026-02-12T19:15:51Z",
"severity": "MODERATE"
},
"details": "## Summary\nAn attacker can cause unbounded memory consumption repeatedly creating and closing many WebTransport streams. Closed streams were not removed from an internal session map, preventing garbage collection of their resources.\n\n## Details\nwebtransport-go maintains an internal map tracking WebTransport streams (both unidirectional and bidirectional) belonging to a session. In affected versions, entries for closed streams were not removed from this map, causing the map to grow indefinitely as streams were created and closed.\n\nA malicious peer can exploit this by opening large numbers of streams and closing them, leading to steady memory growth proportional to the number of closed streams.\n\n## The Fix\nwebtransport-go now removes closed streams from the internal map upon closure. This allows the associated resources to be garbage collected, bounding memory usage to active streams only.",
"id": "GHSA-2f2x-8mwp-p2gc",
"modified": "2026-02-12T22:07:42Z",
"published": "2026-02-12T15:29:11Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/quic-go/webtransport-go/security/advisories/GHSA-2f2x-8mwp-p2gc"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-21438"
},
{
"type": "PACKAGE",
"url": "https://github.com/quic-go/webtransport-go"
},
{
"type": "WEB",
"url": "https://github.com/quic-go/webtransport-go/releases/tag/v0.10.0"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
"type": "CVSS_V3"
}
],
"summary": "webtransport-go: Memory Exhaustion Attack due to Missing Cleanup of Streams Map"
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.