Vulnerability-Lookup

UBUNTU-CVE-2025-62491 (CVE-2025-62491)

Vulnerability from osv_ubuntu – Published: 2025-10-16 16:15 – Updated: 2026-10-17 09:36 – Source website

Details

A Use-After-Free (UAF) vulnerability exists in the QuickJS engine's standard library when iterating over the global list of unhandled rejected promises (ts->rejected_promise_list). * The function js_std_promise_rejection_check attempts to iterate over the rejected_promise_list to report unhandled rejections using a standard list loop. * The reason for a promise rejection is processed inside the loop, including calling js_std_dump_error1(ctx, rp->reason). * If the promise rejection reason is an Error object that defines a custom property getter (e.g., via Object.defineProperty), this getter is executed during the error dumping process. * The malicious custom getter can execute JavaScript code that calls catch() on the same rejected promise being processed. * Calling catch() internally triggers js_std_promise_rejection_tracker, which then removes and frees the current promise entry (JSRejectedPromiseEntry) from the rejected_promise_list. * Since the list iteration continues using the now-freed memory pointer (el), the subsequent loop access results in a Use-After-Free condition.

Severity

8.8 (High)


                    
                      CVSS:4.0/AV:A/AC:H/AT:P/PR:N/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-2025-62491	REPORT
	https://www.cve.org/CVERecord?id=CVE-2025-62491	REPORT
	https://issuetracker.google.com/434195203	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:26.10",
        "name": "quickjs",
        "purl": "pkg:deb/ubuntu/quickjs@2025.04.26-1build1?arch=source\u0026distro=stonking"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2025.04.26-1build1"
      ]
    },
    {
      "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 Use-After-Free (UAF) vulnerability exists in the QuickJS engine\u0027s standard library when iterating over the global list of unhandled rejected promises (ts-\u003erejected_promise_list).   *  The function js_std_promise_rejection_check attempts to iterate over the rejected_promise_list to report unhandled rejections using a standard list loop.   *  The reason for a promise rejection is processed inside the loop, including calling js_std_dump_error1(ctx, rp-\u003ereason).   *  If the promise rejection reason is an Error object that defines a custom property getter (e.g., via Object.defineProperty), this getter is executed during the error dumping process.   *  The malicious custom getter can execute JavaScript code that calls catch() on the same rejected promise being processed.   *  Calling catch() internally triggers js_std_promise_rejection_tracker, which then removes and frees the current promise entry (JSRejectedPromiseEntry) from the rejected_promise_list.   *  Since the list iteration continues using the now-freed memory pointer (el), the subsequent loop access results in a Use-After-Free condition.",
  "id": "UBUNTU-CVE-2025-62491",
  "modified": "2026-10-17T09:36:23Z",
  "published": "2025-10-16T16:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2025-62491"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-62491"
    },
    {
      "type": "REPORT",
      "url": "https://issuetracker.google.com/434195203"
    },
    {
      "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:N/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-2025-62491"
  ]
}

CVE-2025-62491 (GCVE-0-2025-62491)

Vulnerability from cvelistv5 – Published: 2025-10-16 15:51 – Updated: 2025-10-16 18:04

Title

Use-after-free in js_std_promise_rejection_check in QuickJS

Summary

Severity

8.8 (High)


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

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2025-10-16 18:03 UTC

CWE

CWE-416 - Use After Free

Assigner

Google CNA under the Google root

CNA scorecard B 77/100 over 40 records in the last 180 days details

References

2 references

URL	Tags
https://bellard.org/quickjs/Changelog
https://issuetracker.google.com/434195203

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

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2025-62491",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-10-16T18:03:58.190903Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-10-16T18:04:16.529Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://bellard.org/quickjs/",
          "defaultStatus": "unaffected",
          "packageName": "js_std_promise_rejection_check",
          "product": "QuickJS",
          "vendor": "QuickJS",
          "versions": [
            {
              "lessThan": "2025-09-13",
              "status": "affected",
              "version": "2025-04-26",
              "versionType": "date"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Google Big Sleep"
        }
      ],
      "datePublic": "2025-07-24T22:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eA \u003cb\u003eUse-After-Free (UAF)\u003c/b\u003e vulnerability exists in the QuickJS engine\u0027s standard library when iterating over the global list of unhandled rejected promises (\u003ccode\u003ets-\u0026gt;rejected_promise_list\u003c/code\u003e).\u003c/p\u003e\u003col\u003e\u003cli\u003e\u003cp\u003eThe function \u003cb\u003e\u003ccode\u003ejs_std_promise_rejection_check\u003c/code\u003e\u003c/b\u003e attempts to iterate over the \u003ccode\u003erejected_promise_list\u003c/code\u003e to report unhandled rejections using a standard list loop.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eThe \u003cb\u003ereason\u003c/b\u003e for a promise rejection is processed inside the loop, including calling \u003ccode\u003ejs_std_dump_error1(ctx, rp-\u0026gt;reason)\u003c/code\u003e.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eIf the promise \u003cb\u003erejection reason\u003c/b\u003e is an \u003cb\u003eError object\u003c/b\u003e that defines a custom property \u003cb\u003egetter\u003c/b\u003e (e.g., via \u003ccode\u003eObject.defineProperty\u003c/code\u003e), this getter is executed during the error dumping process.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eThe malicious custom getter can execute JavaScript code that calls \u003cb\u003e\u003ccode\u003ecatch()\u003c/code\u003e\u003c/b\u003e on the \u003ci\u003esame\u003c/i\u003e rejected promise being processed.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eCalling \u003ccode\u003ecatch()\u003c/code\u003e internally triggers \u003cb\u003e\u003ccode\u003ejs_std_promise_rejection_tracker\u003c/code\u003e\u003c/b\u003e, which then \u003cb\u003eremoves and frees\u003c/b\u003e the current promise entry (\u003ccode\u003eJSRejectedPromiseEntry\u003c/code\u003e) from the \u003ccode\u003erejected_promise_list\u003c/code\u003e.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eSince the list iteration continues using the now-freed memory pointer (\u003ccode\u003eel\u003c/code\u003e), the subsequent loop access results in a \u003cb\u003eUse-After-Free\u003c/b\u003e condition.\u003c/p\u003e\u003c/li\u003e\u003c/ol\u003e\u003cbr\u003e"
            }
          ],
          "value": "A Use-After-Free (UAF) vulnerability exists in the QuickJS engine\u0027s standard library when iterating over the global list of unhandled rejected promises (ts-\u003erejected_promise_list).\n\n  *  The function js_std_promise_rejection_check attempts to iterate over the rejected_promise_list to report unhandled rejections using a standard list loop.\n\n\n  *  The reason for a promise rejection is processed inside the loop, including calling js_std_dump_error1(ctx, rp-\u003ereason).\n\n\n  *  If the promise rejection reason is an Error object that defines a custom property getter (e.g., via Object.defineProperty), this getter is executed during the error dumping process.\n\n\n  *  The malicious custom getter can execute JavaScript code that calls catch() on the same rejected promise being processed.\n\n\n  *  Calling catch() internally triggers js_std_promise_rejection_tracker, which then removes and frees the current promise entry (JSRejectedPromiseEntry) from the rejected_promise_list.\n\n\n  *  Since the list iteration continues using the now-freed memory pointer (el), the subsequent loop access results in a Use-After-Free condition."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-175",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-175 Code Inclusion"
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "HIGH",
            "attackRequirements": "PRESENT",
            "attackVector": "ADJACENT",
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "LOW",
            "subConfidentialityImpact": "HIGH",
            "subIntegrityImpact": "HIGH",
            "userInteraction": "PASSIVE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L",
            "version": "4.0",
            "vulnAvailabilityImpact": "LOW",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-416",
              "description": "CWE-416 Use After Free",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-10-16T15:51:24.238Z",
        "orgId": "14ed7db2-1595-443d-9d34-6215bf890778",
        "shortName": "Google"
      },
      "references": [
        {
          "url": "https://bellard.org/quickjs/Changelog"
        },
        {
          "url": "https://issuetracker.google.com/434195203"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Use-after-free in js_std_promise_rejection_check in QuickJS",
      "x_generator": {
        "engine": "Vulnogram 0.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "14ed7db2-1595-443d-9d34-6215bf890778",
    "assignerShortName": "Google",
    "cveId": "CVE-2025-62491",
    "datePublished": "2025-10-16T15:51:24.238Z",
    "dateReserved": "2025-10-15T08:47:41.878Z",
    "dateUpdated": "2025-10-16T18:04:16.529Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}

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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Publication & reservation Sightings KEV catalogs Other timestamps

Loading timeline…

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

UBUNTU-CVE-2025-62491 (CVE-2025-62491)

CVE-2025-62491 (GCVE-0-2025-62491)

Tags

Sightings

Nomenclature

Vulnerability timeline

Related by attack behaviour