{"id":"CVE-2024-43367","aliases":["EUVD-2024-2567","GHSA-f67q-wr6w-23jq","RUSTSEC-2024-0444"],"status":"published","title":"Boa has an uncaught exception when transitioning the state of `AsyncGenerator` objects","description":"Boa is an embeddable and experimental Javascript engine written in Rust. Starting in version 0.16 and prior to version 0.19.0, a wrong assumption made when handling ECMAScript's `AsyncGenerator` operations can cause an uncaught exception on certain scripts. Boa'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`. However, 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. Version 0.19.0 is patched to correctly handle this case. Users unable to upgrade to the patched version would want to use `std::panic::catch_unwind` to ensure any exceptions caused by the engine don't impact the availability of the main application.","severity":{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00597,"percentile":0.49031,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-248"],"published":"2024-08-14T12:00:00Z","modified":"2026-10-28T02:30:54Z","fixes":[{"ecosystem":"crates.io","package":"boa_engine","fixed_in":["0.19.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"crates.io","package":"boa_engine","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.16"},{"fixed":"0.19.0"}]}]},{"source":"osv","ecosystem":"crates.io","package":"boa_engine","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.16"},{"fixed":"0.19.0"}]}]},{"source":"osv","ecosystem":"crates.io","package":"boa_engine","ranges":[{"type":"SEMVER","events":[{"introduced":"0.16.0"},{"fixed":"0.19.0"}]}]}],"products":[{"vendor":"boa","product":"boa"},{"vendor":"boa-dev","product":"boa"}],"references":[{"url":"https://github.com/boa-dev/boa/security/advisories/GHSA-f67q-wr6w-23jq","tags":["x_refsource_CONFIRM","advisory","web"]},{"url":"https://github.com/tc39/ecma262/security/advisories/GHSA-g38c-wh3c-5h9r","tags":["x_refsource_MISC","advisory","web"]},{"url":"https://github.com/boa-dev/boa/commit/69ea2f52ed976934bff588d6b566bae01be313f7","tags":["x_refsource_MISC","fix","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2024-43367","tags":["advisory"]},{"url":"https://rustsec.org/advisories/RUSTSEC-2024-0444.html","tags":["web","advisory"]},{"url":"https://github.com/advisories/GHSA-f67q-wr6w-23jq"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/43xxx/CVE-2024-43367.json","tags":["advisory"]},{"url":"https://github.com/boa-dev/boa","tags":["package"]},{"url":"https://crates.io/crates/boa_engine","tags":["package"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2024-43357","tags":["web"]}],"sources":{"cve":[{"id":"CVE-2024-43367","title":"Boa has an uncaught exception when transitioning the state of `AsyncGenerator` objects","description":"Boa is an embeddable and experimental Javascript engine written in Rust. Starting in version 0.16 and prior to version 0.19.0, a wrong assumption made when handling ECMAScript's `AsyncGenerator` operations can cause an uncaught exception on certain scripts. Boa'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`. However, 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. Version 0.19.0 is patched to correctly handle this case. Users unable to upgrade to the patched version would want to use `std::panic::catch_unwind` to ensure any exceptions caused by the engine don't impact the availability of the main application.","status":"published","published":"2024-08-15T20:38:23.53Z","modified":"2024-08-20T15:45:24.595Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-248"],"updated_at":"2026-11-02T14:33:58.839967Z"}],"euvd":[{"id":"EUVD-2024-2567","description":"Boa is an embeddable and experimental Javascript engine written in Rust. Starting in version 0.16 and prior to version 0.19.0, a wrong assumption made when handling ECMAScript's `AsyncGenerator` operations can cause an uncaught exception on certain scripts. Boa'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`. However, 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. Version 0.19.0 is patched to correctly handle this case. Users unable to upgrade to the patched version would want to use `std::panic::catch_unwind` to ensure any exceptions caused by the engine don't impact the availability of the main application.","status":"published","published":"2024-08-15T20:38:23Z","modified":"2024-08-20T15:45:24Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-03T00:56:14.606712Z"}],"ghsa":[{"id":"GHSA-f67q-wr6w-23jq","title":"Boa has an uncaught exception when transitioning the state of `AsyncGenerator` objects","description":"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","status":"published","published":"2024-08-14T20:49:51Z","modified":"2025-12-20T05:28:06Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-248"],"updated_at":"2026-11-02T14:39:14.093341Z"}],"nvd":[{"id":"CVE-2024-43367","description":"Boa is an embeddable and experimental Javascript engine written in Rust. Starting in version 0.16 and prior to version 0.19.0, a wrong assumption made when handling ECMAScript's `AsyncGenerator` operations can cause an uncaught exception on certain scripts. Boa'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`. However, 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. Version 0.19.0 is patched to correctly handle this case. Users unable to upgrade to the patched version would want to use `std::panic::catch_unwind` to ensure any exceptions caused by the engine don't impact the availability of the main application.","status":"published","published":"2024-08-15T21:15:17.777Z","modified":"2026-06-17T07:50:53.867Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-248"],"updated_at":"2026-11-02T14:10:19.135392Z"}],"osv":[{"id":"CVE-2024-43367","title":"Boa has an uncaught exception when transitioning the state of `AsyncGenerator` objects","description":"Boa is an embeddable and experimental Javascript engine written in Rust. Starting in version 0.16 and prior to version 0.19.0, a wrong assumption made when handling ECMAScript's `AsyncGenerator` operations can cause an uncaught exception on certain scripts. Boa'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`. However, 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. Version 0.19.0 is patched to correctly handle this case. Users unable to upgrade to the patched version would want to use `std::panic::catch_unwind` to ensure any exceptions caused by the engine don't impact the availability of the main application.","status":"published","published":"2024-08-15T20:38:23.53Z","modified":"2026-10-28T02:30:54.633086038Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-248"],"updated_at":"2026-11-02T15:44:42.322107Z"},{"id":"GHSA-f67q-wr6w-23jq","title":"Boa has an uncaught exception when transitioning the state of `AsyncGenerator` objects","description":"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","status":"published","published":"2024-08-14T20:49:51Z","modified":"2026-09-10T03:50:17.403000789Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-248"],"updated_at":"2026-11-02T15:46:46.006631Z"},{"id":"RUSTSEC-2024-0444","title":"Uncaught exception when transitioning the state of `AsyncGenerator` objects from within a property getter of `then`","description":"A wrong assumption made when handling ECMAScript's AsyncGenerator operations\ncan cause an uncaught exception on certain scripts.\n\n## Details\n\nBoa's implementation of AsyncGenerator makes the assumption that the state of\nan AsyncGenerator object cannot change while resolving a promise created by\nmethods of AsyncGenerator such as %AsyncGeneratorPrototype%.next,\n%AsyncGeneratorPrototype%.return, or %AsyncGeneratorPrototype%.throw.\n\nHowever, a carefully constructed code could trigger a state transition from\na getter method for the promise's then property, which causes the engine to\nfail an assertion of this assumption, causing an uncaught exception. This\ncould be used to create a Denial Of Service attack in applications that\nrun 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\nstd::panic::catch_unwind to ensure any exceptions caused by the\nengine don't impact the availability of the main application.","status":"published","published":"2024-08-14T12:00:00Z","modified":"2026-10-12T18:00:06.81177253Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","level":"high"}],"updated_at":"2026-11-02T15:53:39.971022Z"}]}}