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CVE-2024-6611VulnerabilityPublished Updated

CVE-2024-6611: Mozilla Firefox · Vulnerability

Affects Mozilla FirefoxSource CVE Database V5

0

Not known to be exploited · CVSS 9.8 Critical : upgrade to 128 as a priority.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.6% chance of exploitation in 30 days – higher than 51% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 128
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 9 Jul 2024

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

What to do

Upgrade Mozilla Firefox to 128.

Affected software

ProductAffectedFixed in
Mozilla FirefoxAffected
  • <128
Fixed in
  • 128

AI-suggested

1. Immediate upgrade to Mozilla Firefox version 128 or later and Thunderbird version 128 or later once official patches are released. 2. If you cannot patch yet, consider deploying browser configuration policies that restrict or disable nested iframe usage where feasible, especially in enterprise environments. 3. Implement network-level monitoring to detect unusual cross-site navigation patterns or iframe activity that could indicate exploitation attempts. 4. Employ Content Security Policy (CSP) headers to limit iframe sources and reduce exposure to malicious cross-site content. 5. Educate users about the risks of visiting untrusted websites and encourage cautious browsing behavior. 6. Review and enhance web application cookie settings to use additional security flags such as Secure and HttpOnly, and consider token-based authentication mechanisms less reliant on cookies. 7. Monitor threat intelligence feeds for emerging exploit code or attack campaigns targeting this vulnerability. 8. Coordinate with IT and security teams to prioritize patch deployment and incident response readiness. 9. For organizations using Firefox ESR (Extended Support Release), verify patch availability and apply updates accordingly. 10. Conduct post-patch validation and penetration testing to ensure the vulnerability is fully mitigated.

Description

A nested iframe, triggering a cross-site navigation, could send SameSite=Strict or Lax cookies. This vulnerability affects Firefox < 128 and Thunderbird < 128.

References

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