CVE-2025-62492 Heap out-of-bounds read in js_typed_array_indexOf in QuickJS
An attacker can trigger a heap out-of-bounds read in QuickJS via TypedArray.indexOf, potentially disclosing adjacent memory contents.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2025-62492?
CVE-2025-62492 is a medium-severity vulnerability in QuickJS, published on 16 Oct 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
A vulnerability stemming from floating-point arithmetic precision errors exists in the QuickJS engine's implementation of TypedArray.prototype.indexOf() when a negative fromIndex argument is supplied.
* The fromIndex argument (read as a double variable, $d$) is used to calculate the starting position for the search.
* If d is negative, the index is calculated relative to the end of the array by adding the array's length (len) to d:
$$d_{new} = d + \text{len}$$
* Due to the inherent limitations of floating-point arithmetic, if the negative value $d$ is extremely small (e.g., $-1 \times 10^{-20}$), the addition $d + \text{len}$ can result in a loss of precision, yielding an outcome that is exactly equal to $\text{len}$.
* The result is then converted to an integer index $k$: $k = \text{len}$.
* The search function proceeds to read array elements starting from index $k$. Since valid indices are $0$ to $\text{len}-1$, starting the read at index $\text{len}$ is one element past the end of the array.
This allows an attacker to cause an Out-of-Bounds Read of one element immediately following the buffer. While the scope of this read is small (one element), it can potentially lead to Information Disclosure of adjacent memory contents, depending on the execution environment.
Weakness: CWE-125
Which versions are affected by CVE-2025-62492?
It affects 1 product.
Products include Quickjs Project Quickjs.
How do I fix CVE-2025-62492?
No fix has been published for CVE-2025-62492 yet. Limit exposure of the affected software until one is available.
Is CVE-2025-62492 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-62492 exists.
Other vulnerabilities in QuickJS
Sources
Also known as DEBIAN-CVE-2025-62492, GHSA-7x74-j54q-cmv6, UBUNTU-CVE-2025-62492.