CVE-2025-12745Public exploit

Heap buffer over-read via stale slice bounds

Published Nov 5, 2025 · Updated Nov 5, 2025

Buffer over-read in QuickJS through eb2c89087def1829ed99630cb14b549d7a98408c allows local users to read beyond an ArrayBuffer. In js_array_buffer_slice, a Symbol.species constructor can resize the source buffer after slice bounds are calculated, and the function copies the stale length without rechecking the reduced byte_length. Executing crafted JavaScript locally performs an out-of-bounds heap read; the demonstrated AddressSanitizer build aborts the interpreter.

CVSS severity7.8
High
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer over-read in QuickJS through eb2c89087def1829ed99630cb14b549d7a98408c allows local users to read beyond an ArrayBuffer. In js_array_buffer_slice, a Symbol.species constructor can resize the source buffer after slice bounds are calculated, and the function copies the stale length without rechecking the reduced byte_length. Executing crafted JavaScript locally performs an out-of-bounds heap read; the demonstrated AddressSanitizer build aborts the interpreter.

The record

CVE
CVE-2025-12745
Published
Nov 5, 2025
Updated
Nov 5, 2025
Vendor
Fabrice Bellard
Product
QuickJS
Classifications
CWE-125, CWE-119, CWE-126
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 5, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 5, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=eb2c89087def1829ed99630cb14b549d7a98408c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Fabrice Bellard · QuickJSversion=eb2c89087def1829ed99630cb14b549d7a98408c

Published CVSS scores

4.8VulDB CNACVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
7.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
4.3VulDB CNAAV:L/AC:L/Au:S/C:P/I:P/A:P
5.3VulDB CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-126Buffer Over-read

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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