What’s Vulnerable › Vulnerabilities

CVE-2024-6611: Incorrect handling of SameSite cookies

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2024-07-09 · updated 2026-06-17
• Weakness: CWE-1275

Description

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

Affected products

• Mozilla Firefox: before 128.0 — fixed in 128.0
• Mozilla Thunderbird: before 128.0 — fixed in 128.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 128.0; Mozilla Thunderbird 128.0. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1844827
• https://www.mozilla.org/security/advisories/mfsa2024-29/
• https://www.mozilla.org/security/advisories/mfsa2024-32/
• https://bugzilla.mozilla.org/show_bug.cgi?id=1844827
• https://www.mozilla.org/security/advisories/mfsa2024-29/
• https://www.mozilla.org/security/advisories/mfsa2024-32/

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