PT-2026-41909 · Mozilla · Thunderbird+1

Lebr0Nli · Published 2026-05-19 · Updated 2026-05-27 · CVE-2026-8955

Positive Technologies (AI Summary)

CVSS v3.1

8.8

High

Base vector

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

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 privilege escalation issue exists within the DOM: Workers component.

Fix

LPE

Improper Privilege Management

Weakness Enumeration

CWE-269

Related Identifiers

ALSA-2026:21378

ALSA-2026:21380

ALSA-2026:21381

ALSA-2026:21382

CVE-2026-8955

OPENSUSE-SU-2026:10813-1

OPENSUSE-SU-2026:10863-1

OPENSUSE-SU-2026:10864-1

Affected Products

Firefox

Thunderbird

References · 107

• https://mozilla.org/en-US/security/advisories/mfsa2026-51/#CVE-2026-8955 · Vendor Advisory
• https://osv.dev/vulnerability/ALSA-2026:21380 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2026-8955 · Security Note
• https://errata.almalinux.org/8/ALSA-2026-21382.html · Vendor Advisory
• https://mozilla.org/en-US/security/advisories/mfsa2026-48/#CVE-2026-8955 · Vendor Advisory
• https://linux.oracle.com/errata/ELSA-2026-21382.html · Vendor Advisory
• https://osv.dev/vulnerability/openSUSE-SU-2026:10863-1 · Vendor Advisory
• https://mozilla.org/security/advisories/mfsa2026-48 · Vendor Advisory
• https://errata.almalinux.org/9/ALSA-2026-21381.html · Vendor Advisory
• https://errata.almalinux.org/10/ALSA-2026-21380.html · Vendor Advisory
• https://mozilla.org/security/advisories/mfsa2026-46 · Vendor Advisory
• https://osv.dev/vulnerability/openSUSE-SU-2026:10813-1 · Vendor Advisory
• https://osv.dev/vulnerability/ALSA-2026:21381 · Vendor Advisory
• https://mozilla.org/security/advisories/mfsa2026-50 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2026-8955 · Vendor Advisory