CVE-2021-38509

Mozilla: Javascript alert box could have been spoofed onto an arbitrary domain

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Severity

Moderate

Red Hat Product Security

6.1

CVSS 3.0

Review impact separately from score.

Published · November 2, 2021

Updated · November 22, 2025

Description

Due to an unusual sequence of attacker-controlled events, a Javascript alert() dialog with arbitrary (although unstyled) contents could be displayed over top an uncontrolled webpage of the attacker's choosing. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

No mitigation is specified in collected source.

CVSS / CWE

CVSS 3.0 · 6.1
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CWE-1021 · Improper Restriction of Rendered UI Layers or Frames