PT-2026-41904 · Mozilla+1 · Firefox+2

Jakub Szymsza · CVE-2026-8950 · Published 2026-05-19 · Updated 2026-06-29

Positive Technologies (AI Summary)

CVSS v3.1

9.3

Critical

Base vector

AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 151 Firefox ESR versions prior to 140.11 Thunderbird versions prior to 151 Thunderbird versions prior to 140.11

Description A same-origin policy bypass exists in the Networking: HTTP component. The same-origin policy is a critical security mechanism that restricts how a document or script loaded from one origin can interact with a resource from another origin.

Recommendations Update to version 151 Update to version 140.11 Update to version 151 Update to version 140.11

Fix

DoS

Origin Validation Error

Weakness Enumeration

CWE-346

Related Identifiers

ALSA-2026:21378

ALSA-2026:21380

ALSA-2026:21381

ALSA-2026:21382

ALSA-2026:22325

ALSA-2026:22643

CVE-2026-8950

OESA-2026-2392

OESA-2026-2393

OESA-2026-2394

OESA-2026-2465

OPENSUSE-SU-2026:10813-1

OPENSUSE-SU-2026:10863-1

OPENSUSE-SU-2026:10864-1

OPENSUSE-SU-2026:21168-1

RHSA-2026:26174

RHSA-2026:26268

RHSA-2026:26269

RHSA-2026:26270

RHSA-2026:26491

RHSA-2026:26492

RHSA-2026:26493

RHSA-2026:26521

RHSA-2026:26536

RHSA-2026:26539

RHSA-2026:26551

RHSA-2026:26606

RHSA-2026:26629

RHSA-2026:26630

RHSA-2026:27715

Affected Products

Firefox

Rocky Linux

Thunderbird

References · 196

• https://osv.dev/vulnerability/DEBIAN-CVE-2026-8950 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-8947 · Security Note
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-8950 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-8388 · Security Note
• https://errata.almalinux.org/10/ALSA-2026-22325.html · Vendor Advisory
• https://linux.oracle.com/errata/ELSA-2026-21381.html · Vendor Advisory
• https://linux.oracle.com/errata/ELSA-2026-21382.html · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-8391 · Security Note
• https://osv.dev/vulnerability/OESA-2026-2465 · Vendor Advisory
• https://osv.dev/vulnerability/ALSA-2026:22643 · Vendor Advisory
• https://errata.almalinux.org/9/ALSA-2026-21378.html · Vendor Advisory
• https://mozilla.org/security/advisories/mfsa2026-51/#CVE-2026-8950 · Vendor Advisory
• https://errata.rockylinux.org/RLSA-2026:22643 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-8968 · Security Note
• https://cve.org/CVERecord?id=CVE-2026-8950 · Security Note