Cross-site Scripting (XSS) Affecting firefox-esr package, versions <102.3.0esr-1


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.88% (55th percentile)

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  • Snyk IDSNYK-ECHOLATEST-FIREFOXESR-18169369
  • published22 Jul 2026
  • disclosed22 Dec 2022

Introduced: 22 Dec 2022

CVE-2022-40956  (opens in a new tab)
CWE-79  (opens in a new tab)

How to fix?

Upgrade Echo:latest firefox-esr to version 102.3.0esr-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream firefox-esr package and not the firefox-esr package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

When injecting an HTML base element, some requests would ignore the CSP's base-uri settings and accept the injected element's base instead. This vulnerability affects Firefox ESR < 102.3, Thunderbird < 102.3, and Firefox < 105.

CVSS Base Scores

version 3.1