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CVE-2026-2758

CRITICALCVSS 9.8/10EPSS 0.48%

Last modified

CVE-2026-2758 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.. EPSS estimates a 0.48% chance of exploitation in the next 30 days.

Description

Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

Metrics

CVSS 3.1
9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.48%

37.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
MozillaFirefox< 115.33.0
MozillaFirefox< 148.0
MozillaFirefox>= 128.0, < 140.8.0
MozillaThunderbird< 140.8.0
MozillaThunderbird< 148.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2026-2758?
Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
How severe is CVE-2026-2758?
CVE-2026-2758 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.48% probability of exploitation in the next 30 days.
How do I fix CVE-2026-2758?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST