CVE-2024-43367 (CVSS 7.5)

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.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-248 CWE-248

References

Other References

https://github.com/boa-dev/boa/commit/69ea2f52ed976934bff588d6b566bae01be313f7 https://github.com/boa-dev/boa/security/advisories/GHSA-f67q-wr6w-23jq https://github.com/tc39/ecma262/security/advisories/GHSA-g38c-wh3c-5h9r

Frequently Asked Questions

What is CVE-2024-43367? +

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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2024-43367? +

CVE-2024-43367 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

How do I check if I'm vulnerable to CVE-2024-43367? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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