CVE-2026-21434

Source
https://cve.org/CVERecord?id=CVE-2026-21434
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-21434.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-21434
Aliases
Related
Published
2026-02-12T18:18:04.821Z
Modified
2026-02-24T07:41:02.469820Z
Severity
  • 5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L CVSS Calculator
Summary
webtransport-go affected by Memory Exhaustion Attack due to Missing Length Check in WT_CLOSE_SESSION Capsule
Details

webtransport-go is an implementation of the WebTransport protocol. From 0.3.0 to 0.9.0, an attacker can cause excessive memory consumption in webtransport-go's session implementation by sending a WTCLOSESESSION capsule containing an excessively large Application Error Message. The implementation does not enforce the draft-mandated limit of 1024 bytes on this field, allowing a peer to send an arbitrarily large message payload that is fully read and stored in memory. This allows an attacker to consume an arbitrary amount of memory. The attacker must transmit the full payload to achieve the memory consumption, but the lack of any upper bound makes large-scale attacks feasible given sufficient bandwidth. This vulnerability is fixed in 0.10.0.

Database specific
{
    "cwe_ids": [
        "CWE-770"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/21xxx/CVE-2026-21434.json",
    "cna_assigner": "GitHub_M"
}
References

Affected packages

Git / github.com/quic-go/webtransport-go

Affected ranges

Type
GIT
Repo
https://github.com/quic-go/webtransport-go
Events

Affected versions

v0.*
v0.3.0
v0.4.0
v0.4.1
v0.4.2
v0.4.3
v0.5.0
v0.5.1
v0.5.2
v0.5.3
v0.6.0
v0.7.0
v0.8.0
v0.9.0

Database specific

source
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-21434.json"