CVE-2025-62493 Vulnerability Analysis & Exploit Details

CVE-2025-62493
Vulnerability Scoring

Analysis In Progress
Analysis In Progress

Attack Complexity Details

  • Attack Complexity:
    Attack Complexity Analysis In Progress
  • Attack Vector:
    Attack Vector Under Analysis
  • Privileges Required: None
    No authentication is required for exploitation.
  • Scope:
    Impact is confined to the initially vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2025-62493 Details

Status: Received on 16 Oct 2025, 16:15 UTC

Published on: 16 Oct 2025, 16:15 UTC

CVSS Release:

CVE-2025-62493 Vulnerability Summary

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 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 ($\text{JS\_LIMB\_BITS}=64$). * The conversion loop iterates $\text{n\_digits}=26$ times, attempting to read 5 bits in each iteration, totaling $26 \times 5 = 130$ bits. * In the final iterations of the loop, the code attempts to read data that spans two limbs: C c = (r->tab[pos] >> shift) | (r->tab[pos + 1] << (JS_LIMB_BITS - shift)); * Since the BigInt was only allocated two limbs, the read operation for r->tab[pos + 1] becomes an Out-of-Bounds Read when pos points to the last valid limb (e.g., $pos=1$). This vulnerability allows an attacker to cause the engine to read and process data from the memory immediately following the BigInt buffer. This can lead to Information Disclosure of sensitive data stored on the heap adjacent to the BigInt object.

Assessing the Risk of CVE-2025-62493

Access Complexity Graph

The exploitability of CVE-2025-62493 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2025-62493

No exploitability data is available for CVE-2025-62493.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2025-62493, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2025-62493, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2025-62493 does not compromise confidentiality.
  • Integrity: None
    CVE-2025-62493 does not impact data integrity.
  • Availability: None
    CVE-2025-62493 does not affect system availability.

CVE-2025-62493 References

External References

CWE Common Weakness Enumeration

CWE-125

CAPEC Common Attack Pattern Enumeration and Classification

  • Overread Buffers CAPEC-540 An adversary attacks a target by providing input that causes an application to read beyond the boundary of a defined buffer. This typically occurs when a value influencing where to start or stop reading is set to reflect positions outside of the valid memory location of the buffer. This type of attack may result in exposure of sensitive information, a system crash, or arbitrary code execution.

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