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Vulnerabilities

Vulnerability · CVE-2025-62493

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

Published Oct 16, 2025 · catalog updated Oct 16, 2025 · QuickJS QuickJS

Last checked Oct 26, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2025-62493. EPSS is 0.38%. Act only if a listed version of QuickJS QuickJS is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium5.9
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.38%
Remediation
Version ranges on file
Affected products
vendor QuickJS QuickJS 2025-04-26 <2025-09-13

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 $\

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor QuickJS QuickJS 2025-04-26 <2025-09-132025-04-26 <2025-09-13

How to fix CVE-2025-62493

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-62493. EPSS is 0.38%. Act only if a listed version of QuickJS QuickJS is installed.

Which versions are affected?

Compare what you have installed with QuickJS QuickJS 2025-04-26 <2025-09-13 2025-04-26 <2025-09-13. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.38%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 16, 2025 · EUVD

    Detected

    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} +

  2. Oct 16, 2025 · EUVD

    Updated

    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} +

Sources

  • CVE.orgVulnerability recordCVE-2025-62493

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-62493

    30-day exploitation probability 0.38%

    first.org
  • EUVDVulnerability recordEUVD-2025-34781

    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 o

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 26, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 26, 2026
  • CVE.orgOct 26, 2026
  • EUVDOct 26, 2026