CVE-2025-62492
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-10-16

Last updated on: 2025-10-30

Assigner: Google Inc.

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.
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Meta Information
Published
2025-10-16
Last Modified
2025-10-30
Generated
2026-05-07
AI Q&A
2025-10-16
EPSS Evaluated
2026-05-05
NVD
CVE-2025-62492
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
quickjs_project quickjs to 2025-09-13 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-125 The product reads data past the end, or before the beginning, of the intended buffer.
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is caused by floating-point arithmetic precision errors in the QuickJS engine's implementation of TypedArray.prototype.indexOf() when a negative fromIndex argument is used. Specifically, when the negative fromIndex is extremely close to zero (like -1e-20), adding it to the array length results in a loss of precision, causing the calculated starting index to be exactly equal to the array length. Since valid indices range from 0 to length-1, starting the search at the array length causes an out-of-bounds read of one element beyond the array.


How can this vulnerability impact me? :

This vulnerability can allow an attacker to perform an out-of-bounds read of one element immediately following the buffer. Although the scope of this read is small, it can potentially lead to information disclosure of adjacent memory contents depending on the execution environment.


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