Is CVE-2026-8947 in the CISA KEV catalog?

No. CVE-2026-8947 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-8947?

CVE-2026-8947 has a CVSS v3 base score of 7.3 (HIGH).

What is the EPSS score for CVE-2026-8947?

CVE-2026-8947 has an EPSS score of 0.41% (34th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-8947?

Upgrade firefox on debian unstable to 151.0-1 or later. Fixes are available for 18 affected products.

CVE & CISA-KEV Catalog

CVE-2026-8947

HIGH

7.3

CVSS v3

NVD

Description

Use-after-free in the DOM: Bindings (WebIDL) component. This vulnerability was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CWE-416Use After Free CWE-825

How to fix

Remediation Available

firefoxDebian

Fixed in:151.0-1CVE-2026-8947

firefoxRed Hat / RHEL

Fixed in:0:140.11.0-1.el10_0RHSA-2026:27715

Fixed in:0:140.11.0-1.el10_2RHSA-2026:21380

Fixed in:0:140.11.0-1.el10_0RHSA-2026:27715

Fixed in:0:140.11.0-1.el10_2RHSA-2026:21380

Fixed in:0:140.11.0-1.el10_0RHSA-2026:27715

Fixed in:0:140.11.0-1.el10_2RHSA-2026:21380

Fixed in:0:140.11.0-1.el10_0RHSA-2026:27715

Fixed in:0:140.11.0-1.el7_9RHSA-2026:26551

Fixed in:0:140.11.0-1.el7_9.ppc64RHSA-2026:26551

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26630

Fixed in:0:140.11.0-1.el8_4RHSA-2026:26629

Fixed in:0:140.11.0-1.el8_10RHSA-2026:21382

Fixed in:0:140.11.0-1.el8_6RHSA-2026:26606

Fixed in:0:140.11.0-1.el8_10RHSA-2026:21382

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26630

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26493

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21378

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21378

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26493

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21378

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26493

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

firefoxRocky

Fixed in:0:140.11.0-1.el10_2RHSA-2026:21380

Fixed in:0:140.11.0-1.el10_0RHSA-2026:27715

Fixed in:0:140.11.0-1.el10_2RHSA-2026:21380

Fixed in:0:140.11.0-1.el10_0RHSA-2026:27715

Fixed in:0:140.11.0-1.el7_9RHSA-2026:26551

Fixed in:0:140.11.0-1.el7_9.ppc64RHSA-2026:26551

Fixed in:0:140.11.0-1.el7_9RHSA-2026:26551

Fixed in:0:140.11.0-1.el8_4RHSA-2026:26629

Fixed in:0:140.11.0-1.el8_10RHSA-2026:21382

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26630

Fixed in:0:140.11.0-1.el8_6RHSA-2026:26606

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26630

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26493

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26493

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21378

firefox-debuginfoRocky

Fixed in:0:140.11.0-1.el10_2RHSA-2026:21380

Fixed in:0:140.11.0-1.el10_0RHSA-2026:27715

Fixed in:0:140.11.0-1.el7_9RHSA-2026:26551

Fixed in:0:140.11.0-1.el7_9.ppc64RHSA-2026:26551

Fixed in:0:140.11.0-1.el8_10RHSA-2026:21382

Fixed in:0:140.11.0-1.el8_4RHSA-2026:26629

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26630

Fixed in:0:140.11.0-1.el8_6RHSA-2026:26606

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26630

Fixed in:0:140.11.0-1.el8_10RHSA-2026:21382

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21378

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21378

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26493

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21378

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

firefox-debuginfoRed Hat / RHEL

Fixed in:0:140.11.0-1.el10_2RHSA-2026:21380

Fixed in:0:140.11.0-1.el10_0RHSA-2026:27715

Fixed in:0:140.11.0-1.el7_9RHSA-2026:26551

Fixed in:0:140.11.0-1.el7_9.ppc64RHSA-2026:26551

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26630

Fixed in:0:140.11.0-1.el8_6RHSA-2026:26606

Fixed in:0:140.11.0-1.el8_10RHSA-2026:21382

Fixed in:0:140.11.0-1.el8_4RHSA-2026:26629

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26630

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26493

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26493

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21378

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21378

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21378

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26493

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

firefox-debugsourceRocky

Fixed in:0:140.11.0-1.el10_0RHSA-2026:27715

Fixed in:0:140.11.0-1.el10_2RHSA-2026:21380

Fixed in:0:140.11.0-1.el10_0RHSA-2026:27715

Fixed in:0:140.11.0-1.el10_2RHSA-2026:21380

Fixed in:0:140.11.0-1.el8_6RHSA-2026:26606

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26630

Fixed in:0:140.11.0-1.el8_10RHSA-2026:21382

Fixed in:0:140.11.0-1.el8_4RHSA-2026:26629

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26630

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21378

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26493

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

firefox-debugsourceRed Hat / RHEL

Fixed in:0:140.11.0-1.el10_0RHSA-2026:27715

Fixed in:0:140.11.0-1.el10_2RHSA-2026:21380

Fixed in:0:140.11.0-1.el10_0RHSA-2026:27715

Fixed in:0:140.11.0-1.el10_2RHSA-2026:21380

Fixed in:0:140.11.0-1.el10_0RHSA-2026:27715

Fixed in:0:140.11.0-1.el10_2RHSA-2026:21380

Fixed in:0:140.11.0-1.el8_10RHSA-2026:21382

Fixed in:0:140.11.0-1.el8_6RHSA-2026:26606

Fixed in:0:140.11.0-1.el8_10RHSA-2026:21382

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26630

Fixed in:0:140.11.0-1.el8_4RHSA-2026:26629

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26630

Fixed in:0:140.11.0-1.el8_10RHSA-2026:21382

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21378

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21378

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26493

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

firefox-x11Rocky

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21378

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21378

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26493

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26493

firefox-x11Red Hat / RHEL

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26493

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26493

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21378

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21378

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26492

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26493

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26491

thunderbirdRocky

Fixed in:0:140.11.0-1.el10_0RHSA-2026:26539

Fixed in:0:140.11.0-1.el10_2RHSA-2026:22325

Fixed in:0:140.11.0-1.el8_10RHSA-2026:22643

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26268

Fixed in:0:140.11.0-1.el8_10RHSA-2026:22643

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26268

Fixed in:0:140.11.0-1.el8_10RHSA-2026:22643

Fixed in:0:140.11.0-1.el8_4RHSA-2026:26270

Fixed in:0:140.11.0-1.el8_6RHSA-2026:26536

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26269

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26521

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

thunderbirdRed Hat / RHEL

Fixed in:0:140.11.0-1.el10_0RHSA-2026:26539

Fixed in:0:140.11.0-1.el10_2RHSA-2026:22325

Fixed in:0:140.11.0-1.el8_4RHSA-2026:26270

Fixed in:0:140.11.0-1.el8_10RHSA-2026:22643

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26268

Fixed in:0:140.11.0-1.el8_6RHSA-2026:26536

Fixed in:0:140.11.0-1.el8_10RHSA-2026:22643

Fixed in:0:140.11.0-1.el8_6RHSA-2026:26536

Fixed in:0:140.11.0-1.el8_10RHSA-2026:22643

Fixed in:0:140.11.0-1.el8_4RHSA-2026:26270

Fixed in:0:140.11.0-1.el8_10RHSA-2026:22643

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26269

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26269

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26521

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26521

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26521

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

thunderbird-debuginfoRocky

Fixed in:0:140.11.0-1.el10_0RHSA-2026:26539

Fixed in:0:140.11.0-1.el10_2RHSA-2026:22325

Fixed in:0:140.11.0-1.el8_10RHSA-2026:22643

Fixed in:0:140.11.0-1.el8_6RHSA-2026:26536

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26268

Fixed in:0:140.11.0-1.el8_4RHSA-2026:26270

Fixed in:0:140.11.0-1.el8_10RHSA-2026:22643

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26269

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26269

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26521

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26521

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26521

thunderbird-debuginfoRed Hat / RHEL

Fixed in:0:140.11.0-1.el10_2RHSA-2026:22325

Fixed in:0:140.11.0-1.el10_0RHSA-2026:26539

Fixed in:0:140.11.0-1.el10_2RHSA-2026:22325

Fixed in:0:140.11.0-1.el10_0RHSA-2026:26539

Fixed in:0:140.11.0-1.el10_2RHSA-2026:22325

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26268

Fixed in:0:140.11.0-1.el8_6RHSA-2026:26536

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26268

Fixed in:0:140.11.0-1.el8_4RHSA-2026:26270

Fixed in:0:140.11.0-1.el8_10RHSA-2026:22643

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26269

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26521

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26269

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26521

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

thunderbird-debugsourceRocky

Fixed in:0:140.11.0-1.el10_0RHSA-2026:26539

Fixed in:0:140.11.0-1.el10_2RHSA-2026:22325

Fixed in:0:140.11.0-1.el10_0RHSA-2026:26539

Fixed in:0:140.11.0-1.el10_2RHSA-2026:22325

Fixed in:0:140.11.0-1.el8_4RHSA-2026:26270

Fixed in:0:140.11.0-1.el8_10RHSA-2026:22643

Fixed in:0:140.11.0-1.el8_6RHSA-2026:26536

Fixed in:0:140.11.0-1.el8_10RHSA-2026:22643

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26268

Fixed in:0:140.11.0-1.el8_10RHSA-2026:22643

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26269

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26269

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26521

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26521

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26521

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

thunderbird-debugsourceRed Hat / RHEL

Fixed in:0:140.11.0-1.el10_0RHSA-2026:26539

Fixed in:0:140.11.0-1.el10_2RHSA-2026:22325

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26268

Fixed in:0:140.11.0-1.el8_4RHSA-2026:26270

Fixed in:0:140.11.0-1.el8_8RHSA-2026:26268

Fixed in:0:140.11.0-1.el8_10RHSA-2026:22643

Fixed in:0:140.11.0-1.el8_6RHSA-2026:26536

Fixed in:0:140.11.0-1.el8_10RHSA-2026:22643

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26521

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26521

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_6RHSA-2026:26521

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26269

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

Fixed in:0:140.11.0-1.el9_8RHSA-2026:21381

Fixed in:0:140.11.0-1.el9_2RHSA-2026:26269

Fixed in:0:140.11.0-1.el9_4RHSA-2026:26174

DeveloperEditionWindows application

Affected:151.0.0Fixed in:151.0.0Mozilla

Affected:115.36.0Fixed in:115.36.0Mozilla

Affected:140.0 140.11.0Fixed in:140.11.0Mozilla

Mozilla Firefox (en-US)Windows application

Affected:140.0 140.11.0Fixed in:140.11.0Mozilla

Affected:115.36.0Fixed in:115.36.0Mozilla

Affected:151.0.0Fixed in:151.0.0Mozilla

Mozilla Thunderbird (en-US)Windows application

Affected:140.11Fixed in:140.11Mozilla

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityLow

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

Exploit Intelligence

0.41%probability of exploitation in 30 days

34thpercentile

Low risk: more likely to be exploited than 34% of all known CVEs.

References

Related Vulnerabilities

Other CWE-416 (Use After Free) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2019-0708	Critical	9.8	100%	KEV + Ransom	-
CVE-2021-31166	Critical	9.8	100%	KEV	Fix
CVE-2015-5119	Critical	9.8	99%	KEV	-
CVE-2010-3962	High	8.1	97%	KEV	-
CVE-2015-0313	Critical	9.8	96%	KEV	Fix
CVE-2017-9798	High	7.5	95%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-15.