{"id":"CVE-2026-47261","sourceIdentifier":"security-advisories@github.com","published":"2026-06-15T21:17:11.153","lastModified":"2026-06-17T16:42:08.350","vulnStatus":"Analyzed","cveTags":[],"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."}],"affected":[{"source":"security-advisories@github.com","affectedData":[{"vendor":"bytecodealliance","product":"wasmtime","versions":[{"version":">= 37.0.0, < 44.0.2","status":"affected"},{"version":">= 25.0.0, < 36.0.10","status":"affected"},{"version":"< 24.0.9","status":"affected"}]}]}],"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"}}]},"weaknesses":[{"source":"security-advisories@github.com","type":"Secondary","description":[{"lang":"en","value":"CWE-284"}]},{"source":"nvd@nist.gov","type":"Primary","description":[{"lang":"en","value":"NVD-CWE-noinfo"}]}],"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"}]}]}],"references":[{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.9","source":"security-advisories@github.com","tags":["Release Notes"]},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.10","source":"security-advisories@github.com","tags":["Release Notes"]},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v44.0.2","source":"security-advisories@github.com","tags":["Release Notes"]},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v45.0.0","source":"security-advisories@github.com","tags":["Release Notes"]},{"url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-2r75-cxrj-cmph","source":"security-advisories@github.com","tags":["Mitigation","Vendor Advisory"]}]}