CVE-2026-34943 (GCVE-0-2026-34943)
Vulnerability from cvelistv5
Published
2026-04-09 18:36
Modified
2026-04-13 20:15
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-248 - Uncaught Exception
Summary
Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime contains a possible panic which can happen when a flags-typed component model value is lifted with the Val type. If bits are set outside of the set of flags the component model specifies that these bits should be ignored but Wasmtime will panic when this value is lifted. This panic only affects wasmtime's implementation of lifting into Val, not when using the flags! macro. This additionally only affects flags-typed values which are part of a WIT interface. This has the risk of being a guest-controlled panic within the host which Wasmtime considers a DoS vector. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.
References
| URL | Tags | |
|---|---|---|
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| bytecodealliance | wasmtime |
Version: < 24.0.7 Version: >= 25.0.0, < 36.0.7 Version: >= 37.0.0, < 42.0.2 Version: >= 43.0.0, < 44.0.1 |
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-34943",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-04-13T20:15:13.926993Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-04-13T20:15:23.994Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "wasmtime",
"vendor": "bytecodealliance",
"versions": [
{
"status": "affected",
"version": "\u003c 24.0.7"
},
{
"status": "affected",
"version": "\u003e= 25.0.0, \u003c 36.0.7"
},
{
"status": "affected",
"version": "\u003e= 37.0.0, \u003c 42.0.2"
},
{
"status": "affected",
"version": "\u003e= 43.0.0, \u003c 44.0.1"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime contains a possible panic which can happen when a flags-typed component model value is lifted with the Val type. If bits are set outside of the set of flags the component model specifies that these bits should be ignored but Wasmtime will panic when this value is lifted. This panic only affects wasmtime\u0027s implementation of lifting into Val, not when using the flags! macro. This additionally only affects flags-typed values which are part of a WIT interface. This has the risk of being a guest-controlled panic within the host which Wasmtime considers a DoS vector. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1."
}
],
"metrics": [
{
"cvssV4_0": {
"attackComplexity": "HIGH",
"attackRequirements": "PRESENT",
"attackVector": "NETWORK",
"baseScore": 5.6,
"baseSeverity": "MEDIUM",
"privilegesRequired": "HIGH",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "ACTIVE",
"vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
"version": "4.0",
"vulnAvailabilityImpact": "HIGH",
"vulnConfidentialityImpact": "NONE",
"vulnIntegrityImpact": "NONE"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-248",
"description": "CWE-248: Uncaught Exception",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-04-09T18:36:51.370Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-m758-wjhj-p3jq",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-m758-wjhj-p3jq"
}
],
"source": {
"advisory": "GHSA-m758-wjhj-p3jq",
"discovery": "UNKNOWN"
},
"title": "Wasmtime panics when lifting `flags` component value"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-34943",
"datePublished": "2026-04-09T18:36:51.370Z",
"dateReserved": "2026-03-31T17:27:08.660Z",
"dateUpdated": "2026-04-13T20:15:23.994Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"vulnrichment": {
"containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-34943\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-04-13T20:15:13.926993Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-04-13T20:15:19.863Z\"}}], \"cna\": {\"title\": \"Wasmtime panics when lifting `flags` component value\", \"source\": {\"advisory\": \"GHSA-m758-wjhj-p3jq\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV4_0\": {\"version\": \"4.0\", \"baseScore\": 5.6, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N\", \"userInteraction\": \"ACTIVE\", \"attackComplexity\": \"HIGH\", \"attackRequirements\": \"PRESENT\", \"privilegesRequired\": \"HIGH\", \"subIntegrityImpact\": \"NONE\", \"vulnIntegrityImpact\": \"NONE\", \"subAvailabilityImpact\": \"NONE\", \"vulnAvailabilityImpact\": \"HIGH\", \"subConfidentialityImpact\": \"NONE\", \"vulnConfidentialityImpact\": \"NONE\"}}], \"affected\": [{\"vendor\": \"bytecodealliance\", \"product\": \"wasmtime\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 24.0.7\"}, {\"status\": \"affected\", \"version\": \"\u003e= 25.0.0, \u003c 36.0.7\"}, {\"status\": \"affected\", \"version\": \"\u003e= 37.0.0, \u003c 42.0.2\"}, {\"status\": \"affected\", \"version\": \"\u003e= 43.0.0, \u003c 44.0.1\"}]}], \"references\": [{\"url\": \"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-m758-wjhj-p3jq\", \"name\": \"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-m758-wjhj-p3jq\", \"tags\": [\"x_refsource_CONFIRM\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime contains a possible panic which can happen when a flags-typed component model value is lifted with the Val type. If bits are set outside of the set of flags the component model specifies that these bits should be ignored but Wasmtime will panic when this value is lifted. This panic only affects wasmtime\u0027s implementation of lifting into Val, not when using the flags! macro. This additionally only affects flags-typed values which are part of a WIT interface. This has the risk of being a guest-controlled panic within the host which Wasmtime considers a DoS vector. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-248\", \"description\": \"CWE-248: Uncaught Exception\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-04-09T18:36:51.370Z\"}}}",
"cveMetadata": "{\"cveId\": \"CVE-2026-34943\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-04-13T20:15:23.994Z\", \"dateReserved\": \"2026-03-31T17:27:08.660Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-04-09T18:36:51.370Z\", \"assignerShortName\": \"GitHub_M\"}",
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
Loading…
Loading…