CVE-2021-42863Public exploitNetwork attack vector

Arbitrary memory access via unchecked TypedArray copy

Published May 12, 2022 · Updated Aug 4, 2024

Buffer overflow in JerryScript fe3a5c0 allows attackers to read or write arbitrary memory through a crafted TypedArray filter call. The ecma_builtin_typedarray_prototype_filter() path copies source-width elements into an output TypedArray that can have a smaller element width, overrunning its destination buffer. Execution requires attacker-controlled JavaScript to replace a TypedArray instance's constructor before filter() runs; the published test aborts the engine, while the reported primitive provides arbitrary memory access.

CVSS severity9.8
Critical
EPSS probability1.70%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in JerryScript fe3a5c0 allows attackers to read or write arbitrary memory through a crafted TypedArray filter call. The ecma_builtin_typedarray_prototype_filter() path copies source-width elements into an output TypedArray that can have a smaller element width, overrunning its destination buffer. Execution requires attacker-controlled JavaScript to replace a TypedArray instance's constructor before filter() runs; the published test aborts the engine, while the reported primitive provides arbitrary memory access.

The record

CVE
CVE-2021-42863
Published
May 12, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 12, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

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.

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No observations available

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

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

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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