CVE-2024-9402 [Critical] | Memory Corruption in Firefox

Memory safety bugs present in Firefox 130, Firefox ESR 128.2, and Thunderbird 128.2. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 131, Firefox ESR < 128.3, Thunderbird < 128.3, and Thunderbird < 131.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.12%	0.62%	+0.49%
2	2025-11-21	0.86%	0.12%	-0.74%
3	2025-11-18	—	0.86%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.12%

0.62%

+0.49%

2025-11-21

0.86%

0.12%

-0.74%

2025-11-18

—

0.86%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
9.8	3.1	CRITICAL	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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: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: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	5.9	134c704f-9b21-4f2e-91b3-4a467353bcc0

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

9.8

3.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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: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: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

5.9

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

OS Trackers for CVE-2024-9402

vendor	priority	summary	link
`alpine`	—	CVE-2024-9402: 3 source package rows (firefox, firefox-esr, thunderbird); 334 state rows across 3 repos (3.20-community, 3.22-community, edge-community); fixed 0, open 334.	https://security.alpinelinux.org/vuln/CVE-2024-9402
`debian`	unimportant	CVE-2024-9402 unimportant priority: Debian including 2 source packages (firefox, thunderbird), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6.	https://security-tracker.debian.org/tracker/CVE-2024-9402
`gentoo`	high	CVE-2024-9402: 3 GLSA(s) (202412-04, 202412-06, 202505-08), 5 atom(s) (dev-lang/spidermonkey, mail-client/thunderbird, mail-client/thunderbird-bin, www-client/firefox, www-client/firefox-bin); latest impact high.	https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2024-9402
`redhat`	high	—	https://access.redhat.com/security/cve/CVE-2024-9402
`suse`	high	CVE-2024-9402 severity important: SUSE including 40 source package names (MozillaFirefox-128.3.1-112.231.1, MozillaFirefox-128.3.1-150200.152.155.1, …), 156 product×package rows across 52 product lines (Container suse/kiosk/firefox-esr, Image SLES12-SP5-SAP-Azure-LI-BYOS-Production, … (52 product lines)): Fixed 156.	https://www.suse.com/security/cve/CVE-2024-9402/
`ubuntu`	medium	CVE-2024-9402 medium priority: Ubuntu including 9 source packages (firefox, mozjs102, …), 65 status rows across 8 suites (bionic, focal, jammy, noble, oracular, plucky, questing, upstream): DNE 34, needs-triage 10, ignored 9, not-affected 9, released 3.	https://ubuntu.com/security/CVE-2024-9402

Affected software / configurations for CVE-2024-9402

Vendor	Product	Version	Raw CPE
mozilla	firefox	< 128.3.0	cpe:2.3:a:mozilla:firefox:::::esr:::*
mozilla	firefox	< 131.0	cpe:2.3:a:mozilla:firefox::::::::
mozilla	thunderbird	< 128.3.0	cpe:2.3:a:mozilla:thunderbird::::::::
mozilla	thunderbird	>= 129.0, < 131.0	cpe:2.3:a:mozilla:thunderbird::::::::

References for CVE-2024-9402

URL	Tags
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1872744%2C1897792%2C1911317%2C1913445%2C1914106%2C1914475%2C1914963%2C1915008%2C1916476	Issue Tracking
https://www.mozilla.org/security/advisories/mfsa2024-46/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2024-47/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2024-49/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2024-50/	Vendor Advisory

URL

CVE-2024-9402

Exploit prediction scoring system (EPSS) score for CVE-2024-9402

Common vulnerability scoring system (CVSS) metrics for CVE-2024-9402

Weakness enumeration for CVE-2024-9402

OS Trackers for CVE-2024-9402

Affected software / configurations for CVE-2024-9402

References for CVE-2024-9402