Vulnerability-Lookup

ubuntu-cve-2025-62496

Vulnerability from osv_ubuntu

Published

2025-10-16 16:15

Modified

2026-05-20 15:22

Summary

Details

A vulnerability exists in the QuickJS engine's BigInt string parsing logic (js_bigint_from_string) when attempting to create a BigInt from a string with an excessively large number of digits. The function calculates the necessary number of bits (n_bits) required to store the BigInt using the formula: $$\text{n_bits} = (\text{n_digits} \times 27 + 7) / 8 \quad (\text{for radix 10})$$ * For large input strings (e.g., $79,536,432$ digits or more for base 10), the intermediate calculation $(\text{n_digits} \times 27 + 7)$ exceeds the maximum value of a standard signed 32-bit integer, resulting in an Integer Overflow. * The resulting n_bits value becomes unexpectedly small or even negative due to this wrap-around. * This flawed n_bits is then used to compute n_limbs, the number of memory "limbs" needed for the BigInt object. Since n_bits is too small, the calculated n_limbs is also significantly underestimated. * The function proceeds to allocate a JSBigInt object using this underestimated n_limbs. * When the function later attempts to write the actual BigInt data into the allocated object, the small buffer size is quickly exceeded, leading to a Heap Out-of-Bounds Write as data is written past the end of the allocated r->tab array.

Severity

7.1 (High)


                    
                      CVSS:4.0/AV:A/AC:H/AT:P/PR:L/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L

8.8 (High)


                    
                      CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2025-62496	REPORT
	https://www.cve.org/CVERecord?id=CVE-2025-62496	REPORT
	https://issuetracker.google.com/434193016	REPORT
	https://bellard.org/quickjs/Changelog	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libquickjs",
            "binary_version": "2021.03.27-1ubuntu0.1~esm1"
          },
          {
            "binary_name": "quickjs",
            "binary_version": "2021.03.27-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:24.04:LTS",
        "name": "quickjs",
        "purl": "pkg:deb/ubuntu/quickjs@2021.03.27-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2021.03.27-1",
        "2021.03.27-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libquickjs",
            "binary_version": "2025.04.26-1"
          },
          {
            "binary_name": "quickjs",
            "binary_version": "2025.04.26-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "quickjs",
        "purl": "pkg:deb/ubuntu/quickjs@2025.04.26-1?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2024.01.13-5",
        "2025.04.26-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libquickjs",
            "binary_version": "2025.04.26-1build1"
          },
          {
            "binary_name": "quickjs",
            "binary_version": "2025.04.26-1build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "quickjs",
        "purl": "pkg:deb/ubuntu/quickjs@2025.04.26-1build1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2025.04.26-1",
        "2025.04.26-1build1"
      ]
    }
  ],
  "aliases": [],
  "details": "A vulnerability exists in the QuickJS engine\u0027s BigInt string parsing logic (js_bigint_from_string) when attempting to create a BigInt from a string with an excessively large number of digits. The function calculates the necessary number of bits (n_bits) required to store the BigInt using the formula: $$\\text{n\\_bits} = (\\text{n\\_digits} \\times 27 + 7) / 8 \\quad (\\text{for radix 10})$$   *  For large input strings (e.g., $79,536,432$ digits or more for base 10), the intermediate calculation $(\\text{n\\_digits} \\times 27 + 7)$ exceeds the maximum value of a standard signed 32-bit integer, resulting in an Integer Overflow.   *  The resulting n_bits value becomes unexpectedly small or even negative due to this wrap-around.   *  This flawed n_bits is then used to compute n_limbs, the number of memory \"limbs\" needed for the BigInt object. Since n_bits is too small, the calculated n_limbs is also significantly underestimated.   *  The function proceeds to allocate a JSBigInt object using this underestimated n_limbs.   *  When the function later attempts to write the actual BigInt data into the allocated object, the small buffer size is quickly exceeded, leading to a Heap Out-of-Bounds Write as data is written past the end of the allocated r-\u003etab array.",
  "id": "UBUNTU-CVE-2025-62496",
  "modified": "2026-05-20T15:22:57Z",
  "published": "2025-10-16T16:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2025-62496"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-62496"
    },
    {
      "type": "REPORT",
      "url": "https://issuetracker.google.com/434193016"
    },
    {
      "type": "REPORT",
      "url": "https://bellard.org/quickjs/Changelog"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:A/AC:H/AT:P/PR:L/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L",
      "type": "CVSS_V4"
    },
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2025-62496"
  ]
}

CVE-2025-62496 (GCVE-0-2025-62496)

Vulnerability from cvelistv5 – Published: 2025-10-16 15:52 – Updated: 2025-10-16 17:26

Title

Integer overflow in js_bigint_from_string in QuickJS

Summary

A vulnerability exists in the QuickJS engine's BigInt string parsing logic (js_bigint_from_string) when attempting to create a BigInt from a string with an excessively large number of digits. The function calculates the necessary number of bits (n_bits) required to store the BigInt using the formula: $$\text{n\_bits} = (\text{n\_digits} \times 27 + 7) / 8 \quad (\text{for radix 10})$$ * For large input strings (e.g., $79,536,432$ digits or more for base 10), the intermediate calculation $(\text{n\_digits} \times 27 + 7)$ exceeds the maximum value of a standard signed 32-bit integer, resulting in an Integer Overflow. * The resulting n_bits value becomes unexpectedly small or even negative due to this wrap-around. * This flawed n_bits is then used to compute n_limbs, the number of memory "limbs" needed for the BigInt object. Since n_bits is too small, the calculated n_limbs is also significantly underestimated. * The function proceeds to allocate a JSBigInt object using this underestimated n_limbs. * When the function later attempts to write the actual BigInt data into the allocated object, the small buffer size is quickly exceeded, leading to a Heap Out-of-Bounds Write as data is written past the end of the allocated r->tab array.

Severity

7.1 (High)


                        
                          CVSS:4.0/AV:A/AC:H/AT:P/PR:L/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator (v2.0.3)

CWE

CWE-190 - Integer Overflow or Wraparound

Assigner

Google

References

2 references

URL	Tags
https://bellard.org/quickjs/Changelog
https://issuetracker.google.com/434193016

Impacted products

1 product

Vendor	Product	Version
QuickJS	QuickJS	Affected: 2025-04-26 , < 2025-09-13 (date)

Date Public

2025-07-24 22:00

Credits

Google Big Sleep

Show details on NVD website

JSON

To clipboard

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              "value": "\u003cp\u003eA vulnerability exists in the QuickJS engine\u0027s BigInt string parsing logic (\u003ccode\u003ejs_bigint_from_string\u003c/code\u003e) when attempting to create a BigInt from a string with an \u003cb\u003eexcessively large number of digits\u003c/b\u003e.\u003c/p\u003e\u003cp\u003eThe function calculates the necessary number of bits (\u003ccode\u003en_bits\u003c/code\u003e) required to store the BigInt using the formula:\u003c/p\u003e\u003cdiv\u003e$$\\text{n\\_bits} = (\\text{n\\_digits} \\times 27 + 7) / 8 \\quad (\\text{for radix 10})$$\u003c/div\u003e\u003col\u003e\u003cli\u003e\u003cp\u003eFor large input strings (e.g., $79,536,432$ digits or more for base 10), the intermediate calculation $(\\text{n\\_digits} \\times 27 + 7)$ exceeds the maximum value of a standard signed 32-bit integer, resulting in an \u003cb\u003eInteger Overflow\u003c/b\u003e.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eThe resulting \u003ccode\u003en_bits\u003c/code\u003e value becomes unexpectedly small or even \u003cb\u003enegative\u003c/b\u003e due to this wrap-around.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eThis flawed \u003ccode\u003en_bits\u003c/code\u003e is then used to compute \u003ccode\u003en_limbs\u003c/code\u003e, the number of memory \"limbs\" needed for the BigInt object. Since \u003ccode\u003en_bits\u003c/code\u003e is too small, the calculated \u003ccode\u003en_limbs\u003c/code\u003e is also \u003cb\u003esignificantly underestimated\u003c/b\u003e.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eThe function proceeds to allocate a \u003cb\u003e\u003ccode\u003eJSBigInt\u003c/code\u003e\u003c/b\u003e object using this underestimated \u003ccode\u003en_limbs\u003c/code\u003e.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eWhen the function later attempts to write the actual BigInt data into the allocated object, the small buffer size is quickly exceeded, leading to a \u003cb\u003eHeap Out-of-Bounds Write\u003c/b\u003e as data is written past the end of the allocated \u003ccode\u003er-\u0026gt;tab\u003c/code\u003e array.\u003c/p\u003e\u003c/li\u003e\u003c/ol\u003e\u003cbr\u003e"
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

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ubuntu-cve-2025-62496

Vulnerability from osv_ubuntu

CVE-2025-62496 (GCVE-0-2025-62496)

Tags

Sightings

Nomenclature