Linux · Security advisory · June 29, 2026

ELSA-2026-21378: Security update for 2 packages

ELSA-2026-21378, released June 29, 2026, fixes 18 CVEs across 2 products. None of them is reported as exploited. Patch Radar priority: High.

High
CVEs closed
18
None rated Critical
Exploited
0
None reported
Exploitation more likely
0
Vendor assessment
Highest EPSS
0.0061
49th percentile

Priority of the 18 CVEs

Patch now 0 Urgent 0 High 18 Routine 0

Fixed package versions

ProductReleaseFixed in
firefoxol 90:140.12.0-1.0.1.el9_8
firefox-x11ol 90:140.12.0-1.0.1.el9_8

CVEs this fix closes

PriorityCVETitleImpactCVSSEPSSExploitation
High CVE-2026-8956 Integer overflow in the Networking: JAR component 9.8 0.0061 None reported
High CVE-2026-8946 Incorrect boundary conditions in the Audio/Video: Web Codecs component 7.5 0.0056 None reported
High CVE-2026-8953 Sandbox escape due to use-after-free in the Disability Access APIs component 9.6 0.0053 None reported
High CVE-2026-8975 Memory safety bugs fixed in Thunderbird 140.11 and Thunderbird 151 8.8 0.0047 None reported
High CVE-2026-8954 Incorrect boundary conditions, integer overflow in the Audio/Video component 7.5 0.0043 None reported
High CVE-2026-8947 Use-after-free in the DOM: Bindings (WebIDL) component 7.5 0.0041 None reported
High CVE-2026-8968 Denial-of-service due to invalid pointer in the Audio/Video: Web Codecs component 7.5 0.0041 None reported
High CVE-2026-8955 Privilege escalation in the DOM: Workers component 8.8 0.0039 None reported
High CVE-2026-8957 Privilege escalation in the Enterprise Policies component 8.8 0.0039 None reported
High CVE-2026-8962 Mitigation bypass in the DOM: Security component 8.1 0.0037 None reported
High CVE-2026-8974 Memory safety bugs fixed in Thunderbird 140.11 and Thunderbird 151 8.8 0.0037 None reported
High CVE-2026-8958 Information disclosure, sandbox escape in the Security: Process Sandboxing component 8.6 0.0034 None reported
High CVE-2026-8961 Spoofing issue in the Form Autofill component 7.5 0.0032 None reported
High CVE-2026-8401 Sandbox escape in the Profile Backup component 9.8 0.0031 None reported
High CVE-2026-8970 Privilege escalation in the Security component 8.8 0.0031 None reported
High CVE-2026-8391 Other issue in the JavaScript Engine component 7.5 0.0030 None reported
High CVE-2026-8388 Incorrect boundary conditions in the JavaScript Engine: JIT component 7.5 0.0024 None reported
High CVE-2026-8950 Same-origin policy bypass in the Networking: HTTP component 9.3 0.0019 None reported
Showing 1 to 18 of 18 1