quic-go webtransport-go up to 0.9.x memory leak

CVSS Meta Temp Score
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CTI Interest Score
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5.2$0-$5k0.00

Summaryinfo

A vulnerability was found in quic-go webtransport-go up to 0.9.x. It has been classified as problematic. This impacts an unknown function. This manipulation causes memory leak. This vulnerability is registered as CVE-2026-21438. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in quic-go webtransport-go up to 0.9.x. It has been declared as problematic. Affected by this vulnerability is an unknown code block. The manipulation with an unknown input leads to a memory leak vulnerability. The CWE definition for the vulnerability is CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. As an impact it is known to affect availability. The summary by CVE is:

webtransport-go is an implementation of the WebTransport protocol. Prior to 0.10.0, 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. This vulnerability is fixed in v0.10.0.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-21438 since 12/29/2025. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

Upgrading to version 0.10.0 eliminates this vulnerability. The upgrade is hosted for download at github.com.

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Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.2

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 5.3
CNA Vector (GitHub_M): 🔒

CVSSv2info

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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Memory leak
CWE: CWE-401 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: webtransport-go 0.10.0

Timelineinfo

12/29/2025 CVE reserved
02/12/2026 +45 days Advisory disclosed
02/12/2026 +0 days VulDB entry created
02/20/2026 +8 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-2f2x-8mwp-p2gc
Status: Confirmed

CVE: CVE-2026-21438 (🔒)
GCVE (CVE): GCVE-0-2026-21438
GCVE (VulDB): GCVE-100-345805

Entryinfo

Created: 02/12/2026 23:49
Updated: 02/20/2026 19:34
Changes: 02/12/2026 23:49 (65), 02/20/2026 19:34 (1)
Complete: 🔍
Cache ID: 216::103

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