{"id":"GHSA-f67q-wr6w-23jq","summary":"Boa has an uncaught exception when transitioning the state of `AsyncGenerator` objects","details":"A wrong assumption made when handling ECMAScript's `AsyncGenerator` operations can cause an uncaught exception on certain scripts.\n\n## Details\n\nBoa's implementation of `AsyncGenerator` makes the assumption that the state of an `AsyncGenerator` object cannot change while resolving a promise created by methods of `AsyncGenerator` such as `%AsyncGeneratorPrototype%.next`, `%AsyncGeneratorPrototype%.return`, or `%AsyncGeneratorPrototype%.throw`.\nHowever, a carefully constructed code could trigger a state transition from a getter method for the promise's `then` property, which causes the engine to fail an assertion of this assumption, causing an uncaught exception. This could be used to create a Denial Of Service attack in applications that run arbitrary ECMAScript code provided by an external user.\n\n## Patches\n\nVersion 0.19.0 is patched to correctly handle this case.\n\n## Workarounds\n\nUsers unable to upgrade to the patched version would want to use [`std::panic::catch_unwind`](https://doc.rust-lang.org/std/panic/fn.catch_unwind.html) to ensure any exceptions caused by the engine don't impact the availability of the main application.\n\n## References\n\n- https://github.com/boa-dev/boa/commit/69ea2f52ed976934bff588d6b566bae01be313f7\n- https://github.com/tc39/ecma262/security/advisories/GHSA-g38c-wh3c-5h9r","aliases":["CVE-2024-43367","RUSTSEC-2024-0444"],"modified":"2026-08-24T00:34:42.025519417Z","published":"2024-08-14T20:49:51Z","related":["CVE-2024-43357","CVE-2024-43367"],"database_specific":{"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2024-08-14T20:49:51Z","nvd_published_at":"2024-08-15T21:15:17Z","cwe_ids":["CWE-248"]},"references":[{"type":"WEB","url":"https://github.com/boa-dev/boa/security/advisories/GHSA-f67q-wr6w-23jq"},{"type":"WEB","url":"https://github.com/tc39/ecma262/security/advisories/GHSA-g38c-wh3c-5h9r"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-43367"},{"type":"WEB","url":"https://github.com/boa-dev/boa/commit/69ea2f52ed976934bff588d6b566bae01be313f7"},{"type":"PACKAGE","url":"https://github.com/boa-dev/boa"},{"type":"WEB","url":"https://rustsec.org/advisories/RUSTSEC-2024-0444.html"}],"affected":[{"package":{"name":"boa_engine","ecosystem":"crates.io","purl":"pkg:cargo/boa_engine"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.16"},{"fixed":"0.19.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2024/08/GHSA-f67q-wr6w-23jq/GHSA-f67q-wr6w-23jq.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}