{"api_version":"1","generated_at":"2026-06-22T05:56:43+00:00","cve":"CVE-2026-47261","urls":{"html":"https://cve.report/CVE-2026-47261","api":"https://cve.report/api/cve/CVE-2026-47261.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-47261","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-47261"},"summary":{"title":"Wasmtime: WASI path_open(TRUNCATE) bypasses `FilePerms::WRITE` host restriction","description":"Wasmtime is a runtime for WebAssembly. In versions prior to 24.0.9, 36.0.10, and 44.0.2, when a filesystem preopen is given DirPerms::all() and FilePerms::READ without FilePerms::WRITE, this access control mechanism can be bypassed via the wasip2 descriptor.open-at or wasip1 path_open interfaces by opening a file with only the OpenFlags::TRUNCATE oflag. The root cause is that the clause handling OpenFlags::TRUNCATE in crates/wasi/src/filesystem.rs (Dir::open_at, lines 967–969) did not set open_mode |= OpenMode::WRITE;, which is later used for the access control check against FilePerms to determine whether opening the file is permitted; the single-line fix adds that missing assignment, after which the affected calls correctly fail with error-code.not-permitted and ERRNO_PERM respectively. Only wasmtime-wasi embeddings that combine DirPerms::MUTATE with FilePerms::READ are affected by this bug. In particular, the Wasmtime project's wasmtime-cli's use of wasmtime-wasi is not affected, because it always sets FilePerms::all() for all preopens. This issue has been fixed in versions 24.0.9, 36.0.10 and44.0.2.","state":"PUBLISHED","assigner":"GitHub_M","published_at":"2026-06-15 21:17:11","updated_at":"2026-06-17 16:42:08"},"problem_types":["CWE-284","NVD-CWE-noinfo","CWE-284 CWE-284: Improper Access Control"],"metrics":[{"version":"3.1","source":"security-advisories@github.com","type":"Secondary","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"HIGH","availabilityImpact":"NONE"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","data":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","version":"3.1"}}],"references":[{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.9","name":"https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.9","refsource":"security-advisories@github.com","tags":["Release Notes"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v44.0.2","name":"https://github.com/bytecodealliance/wasmtime/releases/tag/v44.0.2","refsource":"security-advisories@github.com","tags":["Release Notes"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-2r75-cxrj-cmph","name":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-2r75-cxrj-cmph","refsource":"security-advisories@github.com","tags":["Mitigation","Vendor Advisory"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v45.0.0","name":"https://github.com/bytecodealliance/wasmtime/releases/tag/v45.0.0","refsource":"security-advisories@github.com","tags":["Release Notes"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.10","name":"https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.10","refsource":"security-advisories@github.com","tags":["Release Notes"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-47261","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-47261","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"bytecodealliance","product":"wasmtime","version":"affected >= 37.0.0, < 44.0.2","platforms":[]},{"source":"CNA","vendor":"bytecodealliance","product":"wasmtime","version":"affected >= 25.0.0, < 36.0.10","platforms":[]},{"source":"CNA","vendor":"bytecodealliance","product":"wasmtime","version":"affected < 24.0.9","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2026","cve_id":"47261","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"bytecodealliance","cpe5":"wasmtime","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"rust","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"47261","cve":"CVE-2026-47261","epss":"0.005000000","percentile":"0.387600000","score_date":"2026-06-21","updated_at":"2026-06-22 00:08:34"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-47261","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2026-06-16T12:45:55.792446Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-06-16T12:46:04.260Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"product":"wasmtime","vendor":"bytecodealliance","versions":[{"status":"affected","version":">= 37.0.0, < 44.0.2"},{"status":"affected","version":">= 25.0.0, < 36.0.10"},{"status":"affected","version":"< 24.0.9"}]}],"descriptions":[{"lang":"en","value":"Wasmtime is a runtime for WebAssembly. In versions prior to 24.0.9, 36.0.10, and 44.0.2, when a filesystem preopen is given DirPerms::all() and FilePerms::READ without FilePerms::WRITE, this access control mechanism can be bypassed via the wasip2 descriptor.open-at or wasip1 path_open interfaces by opening a file with only the OpenFlags::TRUNCATE oflag. The root cause is that the clause handling OpenFlags::TRUNCATE in crates/wasi/src/filesystem.rs (Dir::open_at, lines 967–969) did not set open_mode |= OpenMode::WRITE;, which is later used for the access control check against FilePerms to determine whether opening the file is permitted; the single-line fix adds that missing assignment, after which the affected calls correctly fail with error-code.not-permitted and ERRNO_PERM respectively. Only wasmtime-wasi embeddings that combine DirPerms::MUTATE with FilePerms::READ are affected by this bug. In particular, the Wasmtime project's wasmtime-cli's use of wasmtime-wasi is not affected, because it always sets FilePerms::all() for all preopens. This issue has been fixed in versions 24.0.9, 36.0.10 and44.0.2."}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-284","description":"CWE-284: Improper Access Control","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-06-15T19:47:40.366Z","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M"},"references":[{"name":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-2r75-cxrj-cmph","tags":["x_refsource_CONFIRM"],"url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-2r75-cxrj-cmph"},{"name":"https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.9","tags":["x_refsource_MISC"],"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.9"},{"name":"https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.10","tags":["x_refsource_MISC"],"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.10"},{"name":"https://github.com/bytecodealliance/wasmtime/releases/tag/v44.0.2","tags":["x_refsource_MISC"],"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v44.0.2"},{"name":"https://github.com/bytecodealliance/wasmtime/releases/tag/v45.0.0","tags":["x_refsource_MISC"],"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v45.0.0"}],"source":{"advisory":"GHSA-2r75-cxrj-cmph","discovery":"UNKNOWN"},"title":"Wasmtime: WASI path_open(TRUNCATE) bypasses `FilePerms::WRITE` host restriction"}},"cveMetadata":{"assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","assignerShortName":"GitHub_M","cveId":"CVE-2026-47261","datePublished":"2026-06-15T19:47:40.366Z","dateReserved":"2026-05-18T23:03:37.229Z","dateUpdated":"2026-06-16T12:46:04.260Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-06-15 21:17:11","lastModifiedDate":"2026-06-17 16:42:08","problem_types":["CWE-284","NVD-CWE-noinfo","CWE-284 CWE-284: Improper Access Control"],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"HIGH","availabilityImpact":"NONE"},"exploitabilityScore":3.9,"impactScore":3.6}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-06-16T12:45:55.792446Z","id":"CVE-2026-47261","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*","versionEndExcluding":"24.0.9","matchCriteriaId":"E199A623-C250-4390-88C5-3D3567BE2A3F"},{"vulnerable":true,"criteria":"cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*","versionStartIncluding":"25.0.0","versionEndExcluding":"36.0.10","matchCriteriaId":"C92872A6-C672-43D5-98AB-BB9E5A9D10A5"},{"vulnerable":true,"criteria":"cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*","versionStartIncluding":"37.0.0","versionEndExcluding":"44.0.2","matchCriteriaId":"31F391A3-BB50-4827-A6F3-59175BBEB1FD"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"47261","Ordinal":"1","Title":"Wasmtime: WASI path_open(TRUNCATE) bypasses `FilePerms::WRITE` h","CVE":"CVE-2026-47261","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"47261","Ordinal":"1","NoteData":"Wasmtime is a runtime for WebAssembly. In versions prior to 24.0.9, 36.0.10, and 44.0.2, when a filesystem preopen is given DirPerms::all() and FilePerms::READ without FilePerms::WRITE, this access control mechanism can be bypassed via the wasip2 descriptor.open-at or wasip1 path_open interfaces by opening a file with only the OpenFlags::TRUNCATE oflag. The root cause is that the clause handling OpenFlags::TRUNCATE in crates/wasi/src/filesystem.rs (Dir::open_at, lines 967–969) did not set open_mode |= OpenMode::WRITE;, which is later used for the access control check against FilePerms to determine whether opening the file is permitted; the single-line fix adds that missing assignment, after which the affected calls correctly fail with error-code.not-permitted and ERRNO_PERM respectively. Only wasmtime-wasi embeddings that combine DirPerms::MUTATE with FilePerms::READ are affected by this bug. In particular, the Wasmtime project's wasmtime-cli's use of wasmtime-wasi is not affected, because it always sets FilePerms::all() for all preopens. This issue has been fixed in versions 24.0.9, 36.0.10 and44.0.2.","Type":"Description","Title":"Wasmtime: WASI path_open(TRUNCATE) bypasses `FilePerms::WRITE` h"}]}}}