CVE-2026-4726 — Uncontrolled Resource Consumption in Mozilla Firefox

CWE-400 — Uncontrolled Resource ConsumptionCWE-776 — XML Entity Expansion9 documents8 sources
Severity
7.5HIGHNVD
EPSS
0.0%
top 96.03%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
2
Mozilla FirefoxMozilla Thunderbird
Timeline
PublishedMar 24

Description

Denial-of-service in the XML component. This vulnerability was fixed in Firefox 149 and Thunderbird 149.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitability: 3.9 | Impact: 3.6

Affected Packages2 packages

▶NVDmozilla/firefox< 149.0
▶NVDmozilla/thunderbird< 149.0

🔴Vulnerability Details

3
GHSA
GHSA-2r77-x4qh-mhc3: Denial-of-service in the XML component↗2026-03-24
▶
CVEList
Denial-of-service in the XML component↗2026-03-24
▶
OSV
CVE-2026-4726: Denial-of-service in the XML component↗2026-03-24
▶

📋Vendor Advisories

4
Red Hat
firefox: Denial-of-service in the XML component↗2026-03-24
▶
Debian
CVE-2026-4726: firefox - Denial-of-service in the XML component. This vulnerability affects Firefox < 149...↗2026
▶
Mozilla
Mozilla Foundation Security Advisory 2026-20: CVE-2026-4726↗
▶
Mozilla
Mozilla Foundation Security Advisory 2026-23: CVE-2026-4726↗
▶

🕵️Threat Intelligence

1
Wiz
CVE-2026-4726 Impact, Exploitability, and Mitigation Steps | Wiz↗
▶
CVE-2026-4726 — Uncontrolled Resource Consumption | cvebase