How severe is CVE-2026-8388?

CVE-2026-8388 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-8388 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-8388?

CVE-2026-8388 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-8388?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-8388 have an EU (EUVD) identifier?

Yes. CVE-2026-8388 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-29462.

When was CVE-2026-8388 published?

CVE-2026-8388 was published on 2026-05-12 and last updated on 2026-06-30.

CVE-2026-8388

CVE-2026-8388 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-119.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (15th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-29462
Weakness: CWE-119
Affected product: Mozilla Firefox
Published: 2026-05-12
Last modified: 2026-06-30

Description

Incorrect boundary conditions in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 150.0.3, Firefox ESR 115.36, Firefox ESR 140.11, and Thunderbird 140.11.

Frequently asked questions

What is CVE-2026-8388?: Incorrect boundary conditions in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 150.0.3, Firefox ESR 115.36, Firefox ESR 140.11, and Thunderbird 140.11.
How severe is CVE-2026-8388?: CVE-2026-8388 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-8388 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-8388?: CVE-2026-8388 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-8388?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-8388 have an EU (EUVD) identifier?: Yes. CVE-2026-8388 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-29462.
When was CVE-2026-8388 published?: CVE-2026-8388 was published on 2026-05-12 and last updated on 2026-06-30.

References

Affected products (1)

cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*

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