CVE-2019-11757Public exploitNetwork attack vector

Potential crash via IndexedDB locale use-after-free

Published Jan 8, 2020 · Updated Aug 4, 2024

Use-after-free in Mozilla Firefox before 70 allows remote attackers to cause a potentially exploitable crash via crafted IndexedDB values. IndexedDB index-update creation follows an object's prototype chain, retaining a locale reference that can be deleted before later access and triggering heap use-after-free. The issue requires a browser process to handle attacker-controlled web content; impact is a process crash with potential exploitability, while code execution is not established by the advisory.

CVSS severity8.8
High
EPSS probability1.34%
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 Mozilla Firefox before 70 allows remote attackers to cause a potentially exploitable crash via crafted IndexedDB values. IndexedDB index-update creation follows an object's prototype chain, retaining a locale reference that can be deleted before later access and triggering heap use-after-free. The issue requires a browser process to handle attacker-controlled web content; impact is a process crash with potential exploitability, while code execution is not established by the advisory.

The record

CVE
CVE-2019-11757
Published
Jan 8, 2020
Updated
Aug 4, 2024
Vendor
Mozilla
Product
Firefox
Classifications
CWE-416, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 8, 2020CVE 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?

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

  1. Affected versionversion=before 70

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=before 70
Mozilla · Thunderbirdversion=before 68.2
Mozilla · Firefox ESRversion=before 68.2

Published CVSS scores

6.8NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
8.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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-416Use After Free
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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