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Fencer Vulns
medium 6.5

CVE-2024-3855 json

In certain cases the JIT incorrectly optimized MSubstr operations, which led to out-of-bounds reads.

published 2024-04-16 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-32423

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 34%
public exploits
0
none known

Summary

In certain cases the JIT incorrectly optimized MSubstr operations, which led to out-of-bounds reads. This vulnerability affects Firefox < 125.

Patch / fix

  • Mozilla Firefox 125
  • firefox Ubuntu 20.04 LTS 125.0.2+build1-0ubuntu0.20.04.2

ubuntu advisories UBUNTU-CVE-2024-3855

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • firefox-esr openSUSE Tumbleweed 128.5.1-1.1
  • MozillaFirefox openSUSE Tumbleweed 125.0.2-1.1

opensuse advisories openSUSE-SU-2024:14572-1openSUSE-SU-2024:13907-1

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.40% chance of exploitation in the next 30 days, higher than 34% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected products

  • Mozilla Firefox

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.