CVE-2026-8388

MEDIUMNVD 6.56.5—

6.5

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.

CVSS v3: 6.5
EG Score: 6.5(high)
EPSS: 13.3%
KEV: Not listed

Published

May 12, 2026

Last Modified

May 19, 2026

References (5)

security@mozillahttps://bugzilla.mozilla.org/show_bug.cgi?id=2036978
security@mozillahttps://www.mozilla.org/security/advisories/mfsa2026-45/
security@mozillahttps://www.mozilla.org/security/advisories/mfsa2026-47/
security@mozillahttps://www.mozilla.org/security/advisories/mfsa2026-48/
security@mozillahttps://www.mozilla.org/security/advisories/mfsa2026-51/

Vendor Advisories for CVE-2026-8388(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

GHSA-6cv4-3h2g-632h
GitHub Security AdvisoriesMedium
Incorrect boundary conditions in the JavaScript Engine: JIT component. This vulnerability was...

Frequently asked(5)

What is CVE-2026-8388?

CVE-2026-8388 is a medium vulnerability published on May 12, 2026. 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.

When was CVE-2026-8388 disclosed?

CVE-2026-8388 was first published in the National Vulnerability Database on May 12, 2026, with the most recent update on May 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2026-8388 actively exploited?

CVE-2026-8388 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 13.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2026-8388?

CVE-2026-8388 has a CVSS v3 base score of 6.5 (NVD).

How do I remediate CVE-2026-8388?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-8388, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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CVE-2026-8388

📅 Published

🔄 Last Modified

🔗 References (5)

📣 Vendor Advisories for CVE-2026-8388(1)

❓ Frequently asked(5)