QuickJS 0.9.0/3b45d15 TypedArray.prototype.indexOf out-of-bounds

Summaryinfo

A vulnerability, which was classified as problematic, has been found in QuickJS. The impacted element is the function TypedArray.prototype.indexOf. This manipulation causes out-of-bounds. The identification of this vulnerability is CVE-2025-62492. It is possible to initiate the attack remotely. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability has been found in QuickJS and classified as critical. Affected by this vulnerability is the function TypedArray.prototype.indexOf. The manipulation with an unknown input leads to a out-of-bounds vulnerability. The CWE definition for the vulnerability is CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at bellard.org. This vulnerability is known as CVE-2025-62492 since 10/15/2025. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 270724 (Linux Distros Unpatched Vulnerability : CVE-2025-62492), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2025-09-13 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (270724). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

• QuickJS

Version

• 0.9.0
• 3b45d15

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Discussion