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CVE-2024-6603VulnerabilityPublished Updated

CVE-2024-6603: Mozilla Firefox · Vulnerability

Affects Mozilla FirefoxSource CVE Database V5

0

Not known to be exploited · CVSS 7.4 High : upgrade to 128 or 115.13 soon.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score
7.4High
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 128, 115.13
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

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 or 115.13.

Affected software

ProductAffectedFixed in
Mozilla FirefoxAffected
  • <128
  • <115.13
Fixed in
  • 128
  • 115.13

AI-suggested

1. Monitor Mozilla’s official security advisories and apply security updates immediately once patches for CVE-2024-6603 are released. 2. If you cannot patch yet, consider deploying application control or endpoint protection solutions that can detect and block anomalous memory corruption behaviors. 3. Employ network-level protections such as web filtering and intrusion detection systems to limit exposure to potentially malicious content that could trigger exploitation. 4. Conduct internal audits to identify all instances of Firefox and Thunderbird usage across the organization, including ESR versions, and prioritize patching or temporary mitigation measures accordingly. 5. Educate users about the importance of updating browsers and email clients promptly and discourage the use of outdated versions. 6. For high-security environments, consider temporary use of alternative browsers or email clients not affected by this vulnerability until patches are applied. 7. Implement memory protection technologies such as Address Space Layout Randomization (ASLR) and Data Execution Prevention (DEP) to reduce exploitation success likelihood. 8. Maintain robust backup and incident response plans to quickly recover from potential breaches resulting from exploitation.

Description

In an out-of-memory scenario an allocation could fail but free would have been called on the pointer afterwards leading to memory corruption. This vulnerability affects Firefox < 128, Firefox ESR < 115.13, Thunderbird < 115.13, and Thunderbird < 128.

References

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