CVE-2022-31745Public exploitNetwork attack vector

Memory corruption via delayed array length update

Published Dec 22, 2022 · Updated Apr 15, 2025

Use-after-free in Firefox before 101 allows remote attackers to corrupt browser memory through crafted JavaScript array shifts. The SpiderMonkey moveDenseElements path moves an object pointer behind the incremental garbage-collection marking wavefront before updating the dense initialized length, leaving the object unmarked, finalized, and poisoned. A victim must load attacker-controlled script; Mozilla stated that the affected initializedLength-equals-one path was barriered by JIT code and was not exploitable at disclosure.

CVSS severity4.3
Medium
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Firefox before 101 allows remote attackers to corrupt browser memory through crafted JavaScript array shifts. The SpiderMonkey moveDenseElements path moves an object pointer behind the incremental garbage-collection marking wavefront before updating the dense initialized length, leaving the object unmarked, finalized, and poisoned. A victim must load attacker-controlled script; Mozilla stated that the affected initializedLength-equals-one path was barriered by JIT code and was not exploitable at disclosure.

The record

CVE
CVE-2022-31745
Published
Dec 22, 2022
Updated
Apr 15, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-129, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 22, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 15, 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=unspecified <101

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <101

Published CVSS scores

4.3NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
4.3CISA ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-129Improper Validation of Array Index
T1203Exploitation for Client Execution

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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