CVE-2026-126410

Wasmtime 48.0.0 before 48.0.8 TOCTOU UDP Send Policy Bypass via wasip3 Sockets

Published Nov 13, 2026 CVSS 4.0 · 5.3 Medium EPSS < 1% KEV · Not listed
Description
Wasmtime's wasmtime-wasi crate 48.0.0 before 48.0.8, 49.0.0 before 49.0.5, and 50.0.0 before 50.0.1 contains a time-of-check/time-of-use race in the wasip3 wasi:sockets udp-socket host implementation that lets guests bypass socket_addr_check send restrictions. A malicious guest can race udp-socket.send against udp-socket.connect to deliver attacker-controlled datagrams to addresses the policy permits only for receiving.

Analysis

No analysis available yet

Remediation

No remediation available yet

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Description Wasmtime's wasmtime-wasi crate 48.0.0 before 48.0.8, 49.0.0 before 49.0.5, and 50.0.0 before 50.0.1 contains a time-of-check/time-of-use race in the wasip3 wasi:sockets udp-socket host implementation that lets guests bypass socket_addr_check send restrictions. A malicious guest can race udp-socket.send against udp-socket.connect to deliver attacker-controlled datagrams to addresses the policy permits only for receiving.
Title Wasmtime 48.0.0 before 48.0.8 TOCTOU UDP Send Policy Bypass via wasip3 Sockets
First Time appeared Bytecodealliance
Bytecodealliance wasmtime
Weaknesses CWE-367
CPEs cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:*:*:*
Vendors & Products Bytecodealliance
Bytecodealliance wasmtime
References
Metrics cvssV3_1

{'score': 6.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N'}

cvssV4_0

{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N'}

Weaknesses
  • CWE-367

    Time-of-check Time-of-use (TOCTOU) Race Condition

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Nov 13, 2026, 9:35 AM
Reserved
Nov 10, 2026, 9:34 PM
Status
Deferred
Published
Nov 13, 2026, 10:17 AM
Modified
Nov 13, 2026, 10:17 AM