CVE-2026-4725 [Critical] | Use-After-Free in Firefox

CVE-2026-4725 is rated Moderate Risk (41.5/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.02%). Review affected assets and schedule remediation.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-03-25	—	0.02%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-03-25

—

0.02%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
10.0	3.1	CRITICAL	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	6.0	[email protected]
9.3	3.1	CRITICAL	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:N) Service keeps running; no real outage angle.	2.8	5.8	134c704f-9b21-4f2e-91b3-4a467353bcc0

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

10.0

3.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

3.9

6.0

[email protected]

9.3

3.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N): Service keeps running; no real outage angle.

2.8

5.8

134c704f-9b21-4f2e-91b3-4a467353bcc0

OS Trackers for CVE-2026-4725

vendor	priority	summary	link
`alpine`	—	CVE-2026-4725: 1 source package rows (firefox); 128 state rows across 2 repos (3.23-community, edge-community); fixed 0, open 128.	https://security.alpinelinux.org/vuln/CVE-2026-4725
`debian`	not yet assigned	CVE-2026-4725 not yet assigned priority: Debian including 1 source packages (firefox), 1 status rows across 1 suites (sid): resolved 1.	https://security-tracker.debian.org/tracker/CVE-2026-4725
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2026-4725
`suse`	high	—	https://www.suse.com/security/cve/CVE-2026-4725/
`ubuntu`	medium	CVE-2026-4725 medium priority: Ubuntu including 9 source packages (firefox, mozjs102, …), 40 status rows across 6 suites (bionic, focal, jammy, noble, questing, upstream): DNE 16, needs-triage 10, ignored 8, not-affected 5, needed 1.	https://ubuntu.com/security/CVE-2026-4725

Affected software / configurations for CVE-2026-4725

Vendor	Product	Version	Raw CPE
mozilla	firefox	< 149.0	cpe:2.3:a:mozilla:firefox:::::-:::*

References for CVE-2026-4725

URL	Tags
https://bugzilla.mozilla.org/show_bug.cgi?id=2017108	Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-20/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-23/

URL

CVE-2026-4725 | Sandbox escape due to use-after-free in the Graphics: Canvas2D component

Exploit prediction scoring system (EPSS) score for CVE-2026-4725

Common vulnerability scoring system (CVSS) metrics for CVE-2026-4725

Weakness enumeration for CVE-2026-4725

OS Trackers for CVE-2026-4725

Affected software / configurations for CVE-2026-4725

References for CVE-2026-4725