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CVE-2026-100813

Mozilla Firefox vulnerability

8.8 HIGHEPSS 0.23%
  1. Published29 Sept 2026

Description

Invalid pointer in the JavaScript Engine: JIT component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionRequired
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

Mozilla Firefox< 157.0.0
Mozilla Thunderbird< 157.0

Remediation

Fixed in
Mozilla Firefox≥ 157.0.0
Mozilla Thunderbird≥ 157.0

References

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Frequently asked

Is CVE-2026-100813 being actively exploited?

CVE-2026-100813 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.23%.

How severe is CVE-2026-100813?

CVE-2026-100813 has a CVSS 3.1 base score of 8.8, rated high. EPSS estimates a 0.23% probability of exploitation.

Which products are affected by CVE-2026-100813?

Affected products include Mozilla Firefox, Mozilla Thunderbird.

How do I fix CVE-2026-100813?

Upgrade affected software to a fixed version, for example Mozilla Firefox 157.0.0, Mozilla Thunderbird 157.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-100813 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.