CSP violation disclosure via DevTools DNS prefetch
Published Jul 9, 2024 · Updated Oct 30, 2025
Information disclosure in Firefox and Thunderbird before 128 allows remote attackers to learn when a CSP violation occurs through DNS. DevTools creates an anchor for the blocked resource, and normal DOM insertion prefetches its hostname without honoring the page CSP. Exploitation requires DevTools to be open and a crafted page with an attacker-observed DNS name; the lookup reveals only that the CSP violation occurred.
Summary
What happened
Information disclosure in Firefox and Thunderbird before 128 allows remote attackers to learn when a CSP violation occurs through DNS. DevTools creates an anchor for the blocked resource, and normal DOM insertion prefetches its hostname without honoring the page CSP. Exploitation requires DevTools to be open and a crafted page with an attacker-observed DNS name; the lookup reveals only that the CSP violation occurred.
The record
- CVE
- CVE-2024-6612
- Published
- Jul 9, 2024
- Updated
- Oct 30, 2025
- Vendor
- Mozilla
- Product
- Firefox
- Classifications
- CWE-200, T1048.003
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 9, 2024CVE publishedPublication date reported by the CVE source.
- Oct 30, 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.
- Affected versionversion=0 <128
- Affected versionversion=unspecified <128
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- Bug 1880374 poc.htmlproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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