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CVE-2025-62493
MEDIUM · CVSS 6.5
EPSS exploitation probability: 0%
Published 2025-10-16T16:15:39.797 · Last modified 2026-06-17T09:51:58.740

Summary

A vulnerability exists in the QuickJS engine's BigInt string conversion logic (js_bigint_to_string1) due to an incorrect calculation of the required number of digits, which in turn leads to reading memory past the allocated BigInt structure. * The function determines the number of characters (n_digits) needed for the string representation by calculating: $$ \\ \text{n\_digits} = (\text{n\_bits} + \text{log2\_radix} - 1) / \text{log2\_radix}$$ $$$$This formula is off-by-one in certain edge cases when calculating the necessary memory limbs. For instance, a 127-bit BigInt using radix 32 (where $\text{log2\_radix}=5$) is calculated to need $\text{n\_digits}=26$. * The maximum number of bits actually stored is $\text{n\_bits}=127$, which requires only two 64-bit limbs ($\text{JS\_LIM

Affected products

quickjs_project — quickjs

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.