CVE-2025-9181 [Medium] | Security Vulnerability in Firefox

CVE-2025-9181 is rated Low Risk (32.2/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.06%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-01-27	0.04%	0.06%	+0.02%
2	2026-01-15	0.06%	0.04%	-0.02%
3	2025-11-04	—	0.06%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-01-27

0.04%

0.06%

+0.02%

2026-01-15

0.06%

0.04%

-0.02%

2025-11-04

—

0.06%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
6.5	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/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:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:N) Service keeps running; no real outage angle.	2.8	3.6	134c704f-9b21-4f2e-91b3-4a467353bcc0

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

6.5

3.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/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:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:N): Service keeps running; no real outage angle.

2.8

3.6

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

OS Trackers for CVE-2025-9181

vendor	priority	summary	link
`alpine`	—	CVE-2025-9181: 3 source package rows (firefox, firefox-esr, thunderbird); 382 state rows across 2 repos (3.22-community, edge-community); fixed 0, open 382.	https://security.alpinelinux.org/vuln/CVE-2025-9181
`debian`	not yet assigned	CVE-2025-9181 not yet assigned priority: Debian including 3 source packages (firefox, firefox-esr, thunderbird), 11 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 11.	https://security-tracker.debian.org/tracker/CVE-2025-9181
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2025-9181
`suse`	high	CVE-2025-9181 severity important: SUSE including 40 source package names (2.1.3-4.11:qemu-guest-agent-8.2.7-1.1, MozillaFirefox-140.2.0-112.276.1, …), 147 product×package rows across 47 product lines (Container suse/sl-micro/6.0/kvm-os-container, Image SLES12-SP5-SAP-Azure-LI-BYOS-Production, … (47 product lines)): Fixed 144, First Fixed 3.	https://www.suse.com/security/cve/CVE-2025-9181/
`ubuntu`	medium	CVE-2025-9181 medium priority: Ubuntu including 9 source packages (firefox, mozjs102, …), 49 status rows across 7 suites (bionic, focal, jammy, noble, plucky, questing, upstream): DNE 22, needs-triage 10, ignored 9, not-affected 7, released 1.	https://ubuntu.com/security/CVE-2025-9181

Affected software / configurations for CVE-2025-9181

Vendor	Product	Version	Raw CPE
mozilla	firefox	< 128.14.0	cpe:2.3:a:mozilla:firefox:::::esr:::*
mozilla	firefox	< 142.0	cpe:2.3:a:mozilla:firefox:::::-:::*
mozilla	firefox	>= 140.0, < 140.2.0	cpe:2.3:a:mozilla:firefox:::::esr:::*
mozilla	thunderbird	< 128.14.0	cpe:2.3:a:mozilla:thunderbird:::::esr:::*
mozilla	thunderbird	< 142.0	cpe:2.3:a:mozilla:thunderbird:::::-:::*
mozilla	thunderbird	>= 140.0, < 140.2.0	cpe:2.3:a:mozilla:thunderbird:::::esr:::*

References for CVE-2025-9181

URL	Tags
https://bugzilla.mozilla.org/show_bug.cgi?id=1977130	Issue Tracking Permissions Required
https://www.mozilla.org/security/advisories/mfsa2025-64/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-66/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-67/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-70/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-71/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-72/	Vendor Advisory
https://lists.debian.org/debian-lts-announce/2025/08/msg00016.html
https://lists.debian.org/debian-lts-announce/2025/08/msg00018.html

URL

CVE-2025-9181 | Uninitialized memory in the JavaScript Engine component

Exploit prediction scoring system (EPSS) score for CVE-2025-9181

Common vulnerability scoring system (CVSS) metrics for CVE-2025-9181

Weakness enumeration for CVE-2025-9181

OS Trackers for CVE-2025-9181

Affected software / configurations for CVE-2025-9181

References for CVE-2025-9181