CVE-2024-43357 JavaScript specification issue may lead to type confusion and pointer dereference in implementations
A specification flaw in async generators allows type confusion and pointer dereference, potentially enabling code execution or crashes in JavaScript engines.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2024-43357?
CVE-2024-43357 is a high-severity memory corruption vulnerability in tc39 ecma262, published on 15 Aug 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
ECMA-262 is the language specification for the scripting language ECMAScript. A problem in the ECMAScript (JavaScript) specification of async generators, introduced by a May 2021 spec refactor, may lead to mis-implementation in a way that could present as a security vulnerability, such as type confusion and pointer dereference.
The internal async generator machinery calls regular promise resolver functions on IteratorResult (`{ done, value }`) objects that it creates, assuming that the IteratorResult objects will not be then-ables. Unfortunately, these IteratorResult objects inherit from `Object.prototype`, so these IteratorResult objects can be made then-able, triggering arbitrary behaviour, including re-entering the async generator machinery in a way that violates some internal invariants.
The ECMAScript specification is a living standard and the issue has been addressed at the time of this advisory's public disclosure. JavaScript engine implementors should refer to the latest specification and update their implementations to comply with the `AsyncGenerator` section.
## References
- https://github.com/tc39/ecma262/commit/1e24a286d0a327d08e1154926b3ee79820232727 - https://bugzilla.mozilla.org/show_bug.cgi?id=1901411 - https://github.com/boa-dev/boa/security/advisories/GHSA-f67q-wr6w-23jq - https://bugs.webkit.org/show_bug.cgi?id=275407 - https://issues.chromium.org/issues/346692561 - https://www.cve.org/CVERecord?id=CVE-2024-7652
Which versions are affected by CVE-2024-43357?
How do I fix CVE-2024-43357?
No fix has been published for CVE-2024-43357 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2024-43357 being exploited?
There is no known exploitation of CVE-2024-43357 in the wild and no public exploit code.