Is CVE-2026-21438 actively exploited?

No active exploitation of CVE-2026-21438 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-21438 be exploited remotely?

Yes. CVE-2026-21438 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-21438?

CVE-2026-21438 has a CVSS score of 5.3 (MEDIUM) and an EPSS exploitation probability of 0.02%.

HOME VULNERABILITIESCVE-2026-21438

MEDIUM

CVE-2026-21438

CWE-401Published: February 12, 2026· Updated: Feb 13, 2026

5.3

CVSS v3.1

EPSS:0.02%probability of exploitation in 30 daysPercentile:4.0th

Official 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.

NVD Source

Technical Analysis

CVE-2026-21438 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.