Bytecode Alliance Wasmtime up to 48.0.7/49.0.4/50.0.0 with_finality_and_supertype type confusion

CVSS Meta Temp Score
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CTI Interest Score
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2.9$0-$5k0.00+

Summaryinfo

A vulnerability categorized as problematic has been discovered in Bytecode Alliance Wasmtime up to 48.0.7/49.0.4/50.0.0. Affected by this issue is the function StructType::with_finality_and_supertype. Executing a manipulation can lead to type confusion. This vulnerability is tracked as CVE-2026-126409. The attack is restricted to local execution. No exploit exists.

Detailsinfo

A vulnerability was found in Bytecode Alliance Wasmtime up to 48.0.7/49.0.4/50.0.0. It has been declared as problematic. This vulnerability affects the function StructType::with_finality_and_supertype. The manipulation with an unknown input leads to a type confusion vulnerability. The CWE definition for the vulnerability is CWE-843. The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type. As an impact it is known to affect integrity, and availability. CVE summarizes:

Wasmtime 47.0.0 before 48.0.8, 49.0.0 before 49.0.5, and 50.0.0 before 50.0.1 contains a cross-engine type confusion vulnerability because StructType::with_finality_and_supertype does not validate that the supplied supertype belongs to the same Engine. Embedders using multiple engines that create a GC struct type with another engine's supertype can trigger runtime panics or GC heap corruption, causing denial of service; guest WebAssembly cannot trigger it.

The advisory is available at github.com. This vulnerability was named CVE-2026-126409 since 11/10/2026. The exploitation appears to be easy. Local access is required to approach this attack. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 3.0
VulDB Meta Temp Score: 2.9

VulDB Base Score: 3.9
VulDB Temp Score: 3.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 2.0
CNA Vector (VulnCheck): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Type confusion
CWE: CWE-843
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

11/10/2026 CVE reserved
11/13/2026 +3 days Advisory disclosed
11/13/2026 +0 days VulDB entry created
11/13/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Not defined

CNA: VulnCheck
CVE: CVE-2026-126409 (🔒)

GCVE (CVE): GCVE-0-2026-126409
GCVE (VulDB): GCVE-100-436822

Entryinfo

Created: 11/13/2026 11:36
Changes: 11/13/2026 11:36 (74)
Complete: 🔍
Cache ID: 216::103

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