What is CVE-2024-3858?

CVE-2024-3858 is a high-severity vulnerability in Mozilla Firefox, classified under NULL Pointer Dereference. CVSS score: 7.5/10. Published 2024-04-16.

How severe is CVE-2024-3858?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2024-3858 known to be exploited?

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

NULL pointer dereference in Mozilla Firefox

CVE-2024-3858

It was possible to mutate a JavaScript object so that the JIT could crash while tracing it. This vulnerability affects Firefox < 125.

Published 2024-04-16 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.006 (45.0th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 45th percentile — 45.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Mozilla Firefox — versions unspecified

Weakness classification (CWE)

CWE-476 — NULL Pointer Dereference

Public proof-of-concept exploits

References

bugzilla.mozilla.org/show_bug.cgi (Issue Tracking)
www.mozilla.org/security/advisories/mfsa2024-18/ (Vendor Advisory)

Frequently asked questions

What is CVE-2024-3858?: CVE-2024-3858 is a high-severity vulnerability in Mozilla Firefox, classified under NULL Pointer Dereference. CVSS score: 7.5/10. Published 2024-04-16.
How severe is CVE-2024-3858?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2024-3858 known to be exploited?: 4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.