CVE-2023-6859

8.8 highEPSS 1.1%

High (8.8). EPSS 1.1% chance of exploitation in the next 30 days.

A use-after-free condition affected TLS socket creation when under memory pressure. This vulnerability affects Firefox ESR < 115.6, Thunderbird < 115.6, and Firefox < 121.

Severity

CVSS 3.1

8.8 high

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS: 1.1% chance of exploitation in the next 30 days; higher than 65% of CVEs (scores of 2026-10-31)
CWE: CWE-416
Published: 2023-12-19
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

debian:debian_linux
mozilla:firefox
mozilla:firefox_esr
mozilla:thunderbird

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1840144
https://lists.debian.org/debian-lts-announce/2023/12/msg00020.html
https://lists.debian.org/debian-lts-announce/2023/12/msg00021.html
https://security.gentoo.org/glsa/202401-10
https://www.debian.org/security/2023/dsa-5581

Check your stack JSON