CVE-2019-11761Public exploitNetwork attack vector

Privileged-object exposure via canceled data-URI load

Published Jan 8, 2020 · Updated Aug 4, 2024

Access-control bypass in Mozilla Firefox before 70, Firefox ESR before 68.2, and Thunderbird before 68.2 exposes JSONView to remote attackers. After a crafted data-URI form starts a new tab, converter-child.js continues JSONView injection after onStartRequest cancels the channel, placing the cloned object in a retained same-origin about:blank window. Exploitation requires the user to submit the form; the published object exposes minimal capability but defeats a defense-in-depth boundary.

CVSS severity5.4
Medium
EPSS probability0.91%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Access-control bypass in Mozilla Firefox before 70, Firefox ESR before 68.2, and Thunderbird before 68.2 exposes JSONView to remote attackers. After a crafted data-URI form starts a new tab, converter-child.js continues JSONView injection after onStartRequest cancels the channel, placing the cloned object in a retained same-origin about:blank window. Exploitation requires the user to submit the form; the published object exposes minimal capability but defeats a defense-in-depth boundary.

The record

CVE
CVE-2019-11761
Published
Jan 8, 2020
Updated
Aug 4, 2024
Vendor
Mozilla
Product
Firefox
Classifications
CWE-362, CWE-862, T1189
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

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
5.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/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-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CWE-862Missing Authorization
T1189Drive-by Compromise

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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