What is CVE-2024-9401?

CVE-2024-9401 is a critical-severity vulnerability in Mozilla Firefox, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.8/10. Published 2024-10-01.

How severe is CVE-2024-9401?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2024-9401 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Buffer overflow in Mozilla Firefox

CVE-2024-9401

Memory safety bugs present in Firefox 130, Firefox ESR 115.15, 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, Firefox ESR < 115.16, Thunderbird < 128.3, and Thunderbird < 131.

Vulnerability class: Buffer Overflow

Published 2024-10-01 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.007 (53.0th percentile), scored 2026-10-05.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 53.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Mozilla Firefox — versions unspecified
Mozilla Firefox Esr — versions unspecified
Mozilla Thunderbird — versions unspecified

Weakness classification (CWE)

CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer

Public proof-of-concept exploits

fkie-cad/nvd-json-data-feeds

References

bugzilla.mozilla.org/buglist.cgi (Issue Tracking)
www.mozilla.org/security/advisories/mfsa2024-46/ (Vendor Advisory)
www.mozilla.org/security/advisories/mfsa2024-47/ (Vendor Advisory)
www.mozilla.org/security/advisories/mfsa2024-48/ (Vendor Advisory)
www.mozilla.org/security/advisories/mfsa2024-49/ (Vendor Advisory)
www.mozilla.org/security/advisories/mfsa2024-50/ (Vendor Advisory)
af854a3a-2127-422b-91ae-364da2661108

Frequently asked questions

What is CVE-2024-9401?: CVE-2024-9401 is a critical-severity vulnerability in Mozilla Firefox, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.8/10. Published 2024-10-01.
How severe is CVE-2024-9401?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2024-9401 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.