CVE-2026-7321

CRITICALNVD 9.69.6—

9.6

Sandbox escape due to incorrect boundary conditions in the WebRTC: Networking component. This vulnerability was fixed in Firefox 150, Thunderbird 150, Firefox ESR 140.10.1, and Thunderbird 140.10.1.

CVSS v3: 9.6
EG Score: 9.6(high)
EPSS: 15.7%
KEV: Not listed

Published

April 28, 2026

Last Modified

May 1, 2026

Advisory Details (2)

Auto-updated Apr 28, 2026

No patch confirmed yet.

generic

Security Vulnerabilities fixed in Firefox ESR 140.10.1 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-36/

generic

Access Denied

https://bugzilla.mozilla.org/show_bug.cgi?id=2029461

Patch Availability(4)

Vendor / Ecosystem	Fixed in / Patch	Released	Source
redhat	firefox-0:140.10.1-1.el10_2	2026-05-19	redhat
redhat	thunderbird-0:140.10.1-1.el9_8	2026-05-19	redhat
redhat	firefox-0:140.10.1-1.el9_8	2026-05-19	redhat
redhat	thunderbird-0:140.10.1-1.el10_2	2026-05-19	redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-120Buffer Copy without Checking Size (Classic Buffer Overflow)

All Vendor Advisories

(4)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 9× in last 7d / 15× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-05-31 22:30 UTCepss_batch
2026-05-31 00:16 UTCepss_batch
2026-05-29 13:44 UTCepss_batch
2026-05-28 13:44 UTCepss_batch
2026-05-28 13:44 UTCepss_batch
2026-05-27 13:40 UTCepss_batch
2026-05-27 13:40 UTCepss_batch
2026-05-26 13:44 UTCepss_batch
2026-05-26 07:18 UTCepss_batch
2026-05-21 22:43 UTCepss_batch
2026-05-20 22:38 UTCepss_batch
2026-05-20 15:19 UTCEG score recompute
2026-05-20 15:19 UTCVendor advisory
2026-05-20 15:19 UTCGHSA enrichment
2026-05-20 11:22 UTCepss_batch

Frequently asked(5)

What is CVE-2026-7321?

CVE-2026-7321 is a critical vulnerability published on April 28, 2026. Sandbox escape due to incorrect boundary conditions in the WebRTC: Networking component. This vulnerability was fixed in Firefox 150, Thunderbird 150, Firefox ESR 140.10.1, and Thunderbird 140.10.1.

When was CVE-2026-7321 disclosed?

CVE-2026-7321 was first published in the National Vulnerability Database on April 28, 2026, with the most recent update on May 1, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2026-7321 actively exploited?

CVE-2026-7321 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 15.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2026-7321?

CVE-2026-7321 has a CVSS v3 base score of 9.6 (NVD).

How do I remediate CVE-2026-7321?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-7321, 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.

Dependency Blast Radius

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CVE-2026-7321

Published

Last Modified

Advisory Details (2)

Security Vulnerabilities fixed in Firefox ESR 140.10.1 — Mozilla

Access Denied

Patch Availability(4)

Weakness Classification(1)

All Vendor Advisories

Data Freshness Timeline

Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2026-7321?

Same vendor

Same CWE

CVE-2026-7321

📅 Published

🔄 Last Modified

📋 Advisory Details (2)

Security Vulnerabilities fixed in Firefox ESR 140.10.1 — Mozilla

Access Denied

Patch Availability(4)

Weakness Classification(1)

All Vendor Advisories

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2026-7321?

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Advisory Details (2)

Frequently asked(5)

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