How serious is CVE-2026-21438?

This vulnerability has a CVSS score of 5.3 out of 10, classified as MEDIUM severity. Proof-of-concept exploit code is publicly available, making this an active threat.

Is there exploit code available for CVE-2026-21438?

Yes, proof-of-concept exploit code for CVE-2026-21438 is publicly available on GitHub and security research platforms. This increases the risk of active exploitation.

Which products are affected by CVE-2026-21438?

Check the official CVE details for a complete list of affected products and versions.

How do I fix CVE-2026-21438?

To remediate CVE-2026-21438, check for security patches from the vendor. Apply all available updates and security patches. If no patch is available, implement recommended workarounds or security controls to mitigate the risk.

CVE-2026-21438

Medium

|5.3

Exploit Available

Plain English Summary

AI-powered analysis for quick understanding

An attacker can exploit this vulnerability to overwhelm a system by repeatedly opening and closing WebTransport streams, which leads to excessive memory use because the system fails to properly clean up closed streams. This issue occurs in versions prior to 0.10.0, so updating to the latest version is essential to prevent this problem.

Technical Description

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.

CVSS Vector Analysis

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

Confidentiality ImpactNone

Integrity ImpactNone

Availability ImpactLow

ScopeUnchanged

Vector String

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Exploit Resources

Search for proof-of-concept code and exploit modules

GitHub Search Exploit-DB Nuclei Templates Metasploit Vulners

Official References

NIST NVD

Est. Bounty

$724($500-$1K)

Vendor Response

Grade APatched in 0 days

Quick Information

Published

Feb 12, 2026

8 days ago

Last Modified

Feb 13, 2026

8 days ago