CVE-2019-17001Public exploitNetwork attack vector

Cross-site scripting via object-element CSP bypass

Published Jan 8, 2020 · Updated Aug 5, 2024

Cross-site scripting in Mozilla Firefox 69 allows remote attackers to execute JavaScript in a protected document through an object element. A regression moved CSP state from the Principal to the Client, after which object-element JavaScript was not blocked by script-src 'none'. A user must load attacker-controlled content in Firefox 69; the script then runs in the protected document's context and can read script-accessible cookies.

CVSS severity6.1
Medium
EPSS probability0.80%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Mozilla Firefox 69 allows remote attackers to execute JavaScript in a protected document through an object element. A regression moved CSP state from the Principal to the Client, after which object-element JavaScript was not blocked by script-src 'none'. A user must load attacker-controlled content in Firefox 69; the script then runs in the protected document's context and can read script-accessible cookies.

The record

CVE
CVE-2019-17001
Published
Jan 8, 2020
Updated
Aug 5, 2024
Vendor
Mozilla
Product
Firefox
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 8, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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

Published CVSS scores

5.8NIST National Vulnerability DatabaseAV:N/AC:M/Au:N/C:P/I:P/A:N
6.1NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/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-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
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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