{"cve":{"cve_id":"CVE-2026-47261","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":0.00357,"epss_percentile":0.27476,"epss_as_of":"2026-06-23","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.","published_at":"2026-06-15T19:47:40.366000Z","last_modified_at":null,"cvss_v3_score":7.5,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","cvss_v3_severity":"HIGH","cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":null,"ssvc_automatable":null,"ssvc_technical_impact":null,"cwes":["CWE-284"],"nvd_references":["https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-2r75-cxrj-cmph","https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.9","https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.10","https://github.com/bytecodealliance/wasmtime/releases/tag/v44.0.2","https://github.com/bytecodealliance/wasmtime/releases/tag/v45.0.0"],"vuln_status":null,"trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-24T00:09:39.878444Z","updated_at":"2026-06-28T23:30:40.878937Z"},"effective_severity":"HIGH","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"S","name":"Scope","value":"U","value_label":"Unchanged"},{"metric":"C","name":"Confidentiality","value":"N","value_label":"None"},{"metric":"I","name":"Integrity","value":"H","value_label":"High"},{"metric":"A","name":"Availability","value":"N","value_label":"None"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"bytecodealliance","vendor_name":"bytecodealliance","product_slug":"wasmtime","product_name":"wasmtime","version_start":">= 37.0.0, < 44.0.2","version_start_inclusive":true,"version_end":">= 37.0.0, < 44.0.2","version_end_inclusive":true,"cpe23_uri":"cve5:bytecodealliance:wasmtime:>= 37.0.0, < 44.0.2:>= 37.0.0, < 44.0.2"},{"vendor_slug":"bytecodealliance","vendor_name":"bytecodealliance","product_slug":"wasmtime","product_name":"wasmtime","version_start":">= 25.0.0, < 36.0.10","version_start_inclusive":true,"version_end":">= 25.0.0, < 36.0.10","version_end_inclusive":true,"cpe23_uri":"cve5:bytecodealliance:wasmtime:>= 25.0.0, < 36.0.10:>= 25.0.0, < 36.0.10"},{"vendor_slug":"bytecodealliance","vendor_name":"bytecodealliance","product_slug":"wasmtime","product_name":"wasmtime","version_start":"< 24.0.9","version_start_inclusive":true,"version_end":"< 24.0.9","version_end_inclusive":true,"cpe23_uri":"cve5:bytecodealliance:wasmtime:< 24.0.9:< 24.0.9"}],"exploit_refs":[],"news":[],"references":[{"url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-2r75-cxrj-cmph","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.9","source_type":"PATCH","tags":["patch"]},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.10","source_type":"PATCH","tags":["patch"]},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v44.0.2","source_type":"PATCH","tags":["patch"]},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v45.0.0","source_type":"PATCH","tags":["patch"]}],"timeline":[{"type":"published","at":"2026-06-15T19:47:40.366000Z","label":"CVE published","source":null},{"type":"cvss_changed","at":"2026-06-28T17:54:57.553414Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:54:57.553414Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:54:57.553414Z","label":"CVSS score revised","source":"cvelistv5"}]}