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CVE-2024-9392VulnerabilityPublished Updated

CVE-2024-9392: Mozilla Firefox · Compromised content process can bypass site isolation

Affects Mozilla FirefoxSource CVE Database V5

0

Not known to be exploited · CVSS 9.8 Critical · fixed in 131 : patch Mozilla Firefox as a priority.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 44% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 131, 128.3, 115.16
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 1 Oct 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 2026-10-25.

What to do

Upgrade Mozilla Firefox to 131, 128.3 or 115.16.

Affected software

ProductAffectedFixed in
Mozilla FirefoxAffected
  • <131
  • <128.3
  • <115.16
Fixed in
  • 131
  • 128.3
  • 115.16

AI-suggested

To mitigate CVE-2024-9392, European organizations should immediately verify the versions of Firefox and Thunderbird deployed across their environments and upgrade to the latest patched versions (Firefox 131 or later, Firefox ESR 128.3 or later, Thunderbird 128.3 or later). Since the vulnerability allows bypassing site isolation, it is critical to ensure that all browser instances are updated to prevent exploitation. Organizations should also implement strict application whitelisting and endpoint detection and response (EDR) solutions to monitor for anomalous browser behavior indicative of exploitation attempts. Network-level protections such as web filtering and intrusion detection systems should be tuned to detect suspicious cross-origin requests or unusual browser process activity. User education on the importance of timely updates and cautious browsing habits remains important, although user interaction is not required for exploitation. For high-security environments, consider deploying browser isolation technologies or sandboxing to further contain potential compromises. Finally, maintain up-to-date incident response plans to quickly address any detected exploitation attempts.

Description

A compromised content process could have allowed for the arbitrary loading of cross-origin pages. This vulnerability affects Firefox < 131, Firefox ESR < 128.3, Firefox ESR < 115.16, Thunderbird < 128.3, and Thunderbird < 131.

References

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