Vulnerability DatabaseCVE-2026-126407
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CVE-2026-126407
Published:November 13, 2026
Updated:November 13, 2026
Wasmtime before 36.0.20, 37.0.0 before 48.0.8, 49.0.0 before 49.0.5, and 50.0.0 before 50.0.1 allocates untracked host memory when a component receives a borrow of a resource it defines itself, bypassing the per-store handle limit. A malicious guest component can repeatedly transfer such borrowed resources to consume arbitrary host memory, causing denial of service.
Affected Packages
https://github.com/bytecodealliance/wasmtime.git (GITHUB):
Affected version(s) >=v12.0.0 <v36.0.20 || >=v13.0.0 <v36.0.20 || >=v14.0.0 <v36.0.20 || >=v15.0.0 <v36.0.20 || =v16.0.0 <v36.0.20 || >=v17.0.0 <v36.0.20 || >=v18.0.0 <v36.0.20 || >=v19.0.0 <v36.0.20 || >=v20.0.0 <v36.0.20 || >=v21.0.0 <v36.0.20 || >=v22.0.0 <v36.0.20 || >=v23.0.0 <v36.0.20 || >=v24.0.0 <v36.0.20 || >=v25.0.0 <v36.0.20 || >=v26.0.0 <v36.0.20 || =v27.0.0 <v36.0.20 || >=v28.0.0 <v36.0.20 || >=v29.0.0 <v36.0.20 || >=v30.0.0 <v36.0.20 || =v31.0.0 <v36.0.20 || >=v32.0.0 <v36.0.20 || >=v33.0.0 <v36.0.20 || >=v34.0.0 <v36.0.20 || =v35.0.0 <v36.0.20 || >=v36.0.0 <v36.0.20
Fix Suggestion:
Update to version v36.0.20
https://github.com/bytecodealliance/wasmtime.git (GITHUB):
Affected version(s) >=v37.0.0 <v48.0.8 || >=v38.0.1 <v48.0.8 || >=v39.0.0 <v48.0.8 || >=v40.0.0 <v48.0.8 || >=v41.0.0 <v48.0.8 || >=v42.0.0 <v48.0.8 || >=v43.0.0 <v48.0.8 || >=v44.0.0 <v48.0.8 || >=v45.0.0 <v48.0.8 || >=v46.0.0 <v48.0.8 || >=v47.0.0 <v48.0.8 || >=v48.0.0 <v48.0.8
Fix Suggestion:
Update to version v48.0.8
https://github.com/bytecodealliance/wasmtime.git (GITHUB):
Affected version(s) >=v50.0.0-rc.1 <v50.0.1
Fix Suggestion:
Update to version v50.0.1
https://github.com/bytecodealliance/wasmtime.git (GITHUB):
Affected version(s) >=v49.0.0-rc.1 <v49.0.5
Fix Suggestion:
Update to version v49.0.5
wasmtime (RUST):
Affected version(s) >=50.0.0-rc.1 <50.0.1
Fix Suggestion:
Update to version 50.0.1
wasmtime (RUST):
Affected version(s) >=37.0.0 <48.0.8 || >=41.0.0 <48.0.8 || >=38.0.0 <48.0.8 || >=40.0.0 <48.0.8 || >=42.0.0 <48.0.8 || >=39.0.0 <48.0.8 || >=48.0.0 <48.0.8 || >=46.0.0 <48.0.8 || >=47.0.0 <48.0.8 || >=44.0.0 <48.0.8 || >=45.0.0 <48.0.8 || >=43.0.0 <48.0.8
Fix Suggestion:
Update to version 48.0.8
wasmtime (RUST):
Affected version(s) >=23.0.0 <36.0.20 || >=29.0.0 <36.0.20 || >=30.0.0 <36.0.20 || >=26.0.0 <36.0.20 || =27.0.0 <36.0.20 || =35.0.0 <36.0.20 || >=33.0.0 <36.0.20 || >=32.0.0 <36.0.20 || >=34.0.0 <36.0.20 || =31.0.0 <36.0.20 || >=24.0.0 <36.0.20 || >=28.0.0 <36.0.20 || >=36.0.0 <36.0.20 || >=21.0.0 <36.0.20 || >=22.0.0 <36.0.20 || >=25.0.0 <36.0.20
Fix Suggestion:
Update to version 36.0.20
wasmtime (RUST):
Affected version(s) >=49.0.0-rc.1 <49.0.5
Fix Suggestion:
Update to version 49.0.5
Related Resources (3)
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-6fr9-xmw9-5352
https://www.vulncheck.com/advisories/wasmtime-before-36.0.20-denial-of-service-via-borrowed-resource-transfer
https://nvd.nist.gov/vuln/detail/CVE-2026-126407
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CVSS v4
Base Score:
5.9
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
PRESENT
Privileges Required
LOW
User Interaction
PASSIVE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
4.8
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
Allocation of Resources Without Limits or Throttling
CWE-770