5.3

CVE-2026-21438: webtransport-go affected by a Memory Exhaustion Attack due to Missing Cleanup of Streams Map

Analyzed
AliasesCGA-277j-j8r8-hw8hCGA-2q9h-gmjq-473wCGA-385f-vp8h-jx8p
Published 12-02-2026Last modified 17-02-2026

Vulnerability summary

CVE-2026-21438 is a medium (CVSS 5.3) vulnerability in quic-go webtransport-go. EPSS estimates a 0.41% chance of exploitation in the next 30 days, higher than 35.5% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.3, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.41%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2 · Related 3
OPENSUSE-SU-2026:21483-1SUSE-SU-2026:0757-1CGA-997M-FC67-HM44

Timeline

  1. 12-02-2026
    PublishedVulnerability first disclosed.
  2. 17-02-2026
    Last modifiedVulnerability information updated.

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 metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.41%

Chance of exploitation in the next 30 days

Percentile

36%

Versus all other CVEs

30-day change

Increase +0.02 pp

From 0.39% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard18 products
  • ipfs-cluster< 1.1.5-r5
  • ipfs-cluster-fips< 1.1.5-r4
  • k3s< 1.35.1.1-r1
  • k3s-1.31< 1.31.6.1-r13
  • k3s-1.32< 1.32.13.1-r2
Wolfi9 products
  • ipfs-cluster< 1.1.5-r5
  • k3s< 1.35.1.1-r1
  • k3s-1.32< 1.32.13.1-r2
  • k3s-1.33< 1.33.9.1-r3
  • k3s-static< 1.35.1.1-r1
Github.com/quic-go1 product
  • webtransport-go< 0.10.0
Quic-go1 product

4 vendors · 29 products

References

5 links