CVE-2025-62492
Heap out-of-bounds read in js_typed_array_indexOf in QuickJS
Published Oct 16, 2025
CVSS 4.0 · 5.9 Medium
EPSS < 1%
KEV · Not listed
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.
* 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.
Affected Products
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CVE record
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NVD configurations
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Red Hat packages
No data
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OpenCVE enrichment
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| QuickJS | QuickJS | unaffected |
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No data.
| Vendor | Product | Versions |
|---|---|---|
| Quickjs-ng | Quickjs | — |
Remediation
Tracking
Advisories
Metrics
Attack Vector Adjacent Network
Attack Complexity High
Privileges Required Low
Attack Requirements Present
User Interaction Passive
Vulnerable System Confidentiality Impact High
Vulnerable System Integrity Impact Low
Vulnerable System Availability Impact Low
Subsequent System Confidentiality Impact High
Subsequent System Integrity Impact Low
Subsequent System Availability Impact Low
Attack Vector Adjacent Network
Attack Complexity Low
Privileges Required None
Scope Unchanged
Confidentiality Impact High
Integrity Impact None
Availability Impact None
User Interaction None
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.399% probability within 30 days)
Exploitation poc
Automatable no
Technical Impact partial
References
History
Oct 30, 2025 4:30 PM
First appearance in the feed. Affected versions updated. Affected vendors updated. Scoring metrics updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Quickjs Project
Quickjs Project quickjs |
|
| CPEs | cpe:2.3:a:quickjs_project:quickjs:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Quickjs Project
Quickjs Project quickjs |
|
| Metrics |
cvssV3_1
|
Oct 21, 2025 9:45 AM
First appearance in the feed. Affected vendors updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Quickjs-ng
Quickjs-ng quickjs |
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| Vendors & Products |
Quickjs-ng
Quickjs-ng quickjs |
Oct 16, 2025 6:15 PM
Scoring metrics updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
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Oct 16, 2025 4:00 PM
Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | Heap out-of-bounds read in js_typed_array_indexOf in QuickJS | |
| Weaknesses | CWE-125 | |
| References |
| |
| Metrics |
cvssV4_0
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Subscriptions
Weaknesses
